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NURSYAFIQA ARISYA BINTI JAMALUDIN (A21SC0294)

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NURSYAFIQA ARISYA BINTI JAMALUDIN (A21SC0294)

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Group VIIA (halogen)
-consist of 7 valence electron
-forming singly bonded diatomic molecules

Down the group
-melting point increase
-colour intensity increase
-atomic and ionic radius increase
-density increase
-ionization energy decrease
-electronegativity decrease
-oxidizing power decrease

In industries, it can be prepared by
-electrolysis of HF dissolved in molten KF (Fluorine)
-electrolysis of molten NaCl in Down Cells, electrolysis of brine in kellner-solvay method [use chlor-alkali cell] (chlorine)
-passing chlorine gas into conc. sea water (bromine)

In laboratory, it can be prepared by
-reaction between solutions of halide ions with any substances that are strong oxidizing agent
-reaction between metal halide with strong oxidizing agent in presence of acid

Application of halogen
-as agent for organic compound (fluorine)
-manufacturing of organic and inorganic chemicals in paper and pulp industries, water treatment, cleaning&sanitation (chlorine)
-manufacturing of fuel additives, flame retardants, plants protection agents, manufacturing of organic molecule (bromine)

Chemical properties
-oxidizing agent
-react with H2S
-react with water (except for F2)
-react with alkali solution
-react with non-metallic elements
-react with metal

Compound of halogen
-Oxoacid of halogen
-Hydrogen halides
-Oxyanion and salts of halogen

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NUR ATHIRAH ALIAH BINTI JAMIL (A21SC0222)

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NUR ATHIRAH ALIAH BINTI JAMIL (A21SC0222)

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GROUP VIIA (HALOGEN)

- 7 valence electrons, need one electron to achieve a noble gas configuration
- form singly bonded diatomic molecules

Down the group:
Increasing in:
-melting point & boiling point
-colour intensity
-atomic radius & ionic radius
-density
Decreasing in:
- ionization energy
- electronegativity
- oxidizing power

Fluorine
- the highest electronegativity in periodic table
- need 1 more electron to fulfill the octet
- due to high electronegativity, can easily remove an electron
- isoelectronic with a noble gas

Industrial preparation
*Fluorine*
~ Obtain by an electrolysis of HF dissolve in molten KF
*Chlorine*
~ electrolysis of molten NaCl in Downs Cell
~ electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell

*Bromine*
~ by passing chlorine gas into conc. sea water

Laboratory preparation
1) reaction a solution of the halide ions with any substance that is stronger oxidizing agent

2) reaction of metal halide, MX with strong oxidizing agent in presence not acid

3) chlorine made by oxidation of conc. HCl with MnO₂ / KMnO₄

4) a solution of Cl₂ in water readily obtain by reacting bleaching powder, CaCl₂•Ca(ClO)₂ @ bleaching solution, NaOCl with HCl

Application of Elemental Halogen
*Fluorine*

‌Fluorinating agent for organic compound

‌refrigerant fluids

aerosol propellants

*Chlorine*

‌in water treatment

in cleaning and sanitation‌

in manufacture of organic and inorganic chemicals‌

in paper and pulp industry

*Bromine*

‌manufacture of organic chemicals

🧪Chemical Properties🧪
-as oxidizing agent (due to high electronegativity)
-Displacement reaction

down the group⬇️, oxidizing power⬇️
F₂ > Cl₂ > Br₂ > I₂
-Reaction with H₂S
- react with H₂O(except F₂)
-react with alkali solution
-react with non-metallic elements
-react with metal

Compounds of Halogen

Industrial preparation:
📌 HF
- manufactured by reaction of fluorspar with H₂SO₄
- semiconductor manifacture

📌 HCL, HBr, HI
- manifactured by direct of hydrogen and halogen

Laboratory preparation:
📌 HCL, HBr, HI
- reaction of halide salt with conc. H₂SO₄(not suitable method for HBr & HI)
- reaction of phosphoric acid with halide salt in presence P₂O₅

📍Physical Properties of HX📍
Thermal stability: HF > HCl > HBr > HI
Acid strength: HF << HCl < HBr < HI

📍 Chemical Properties 📍

‌reacts with metal above hydrogen in the Electrochemical Series

reacts with metal oxides, hydroxides, carbonates

HF reacts with glass

HX as reducing agent

Strength as reducing agent:
HCl < HBr < HI

4 Type of Oxoacid of Halogen, preparation:

1) Hypohalous, HOX (oxidation state: +1)
- Hydrolysis of Halogen: disproportionation reaction
- Cl ₂ , Br 2 and I ₂ are slightly soluble in water
- Industrial preparation of HOCl: Hydrolysis of Cl ₂ O

2) Halous acid, HOXO (oxidation state: +3)
- chlorous acid is prepared by reaction of chlorine dioxide with hydrogen peroxide in the presence of barium hydroxide.
-The barium chloride precipitated is then reacted with sulfuric acid to release chlorous acid

3) Halic acid, HOXO ₂ (oxidation state: +5)
- only HOIO₂ can easily be prepared and isolated from its aq solution. Prepared by reaction of iodine with nitric acid

4) Perhalic acid, HOXO ₃ (oxidation state: +7)
- HOClO ₃ (perchloric acid) and HOIO ₃(periodic acid) can be prepared from the catalytic oxidation of the corresponding halate , XO ₃⁻  followed by addition of a strong acid

Acid strength of oxoacid of chlorine:
HOCl < HOClO < HOClO₂ < HOClO₃

Oxyanion and salts of halogen:

Hypochlorite ion (+1) and its salt
Preparation :
# electrolysis of cold (15°C) brine( Chlor-alkali industry)
# Reaction of CaO or Ca(OH)₂ with chlorine

Halite ion (+3)and its salts
Preparation:
# salts are produced by reaction of ClO₂ with NaOH and H₂O₂

Halate ion (+5) and its salts
Preparation:
# electrolysis of hot (70°C) brine

🔖Oxides of halogen🔖

Dichlorine  hexoxide, Cl₂O₆

✓ highly unstable molecule
✓ (solid phase) mixture of anhydride of chloric and perchloric acid, ClO₂+  ClO₄⁻

Dichlorine heptoxide

✓ prepared by carefully dehydrating conc. perchloric acid with P₂O₅.
✓ distilling the product -35°C under 1mm Hg pressure

Diiodine pentoxide, I₂O₅

✓ white solid compound and decompose only at  temp high > 300°C
✓ prepared by dehydrating iodic acid at 200°C in a steam of dry air

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Group VIIA (Halogen)

The Group VIIA elements are called halogens.

Halogens are highly reactive nonmetallic elements in the periodic table.

Astatine is radioactive and rapidly decays to other, least reactive compared to other Group VIIA elements.

have seven valence electrons in their highest-energy orbitals (ns²np⁵).  Receive an electron to achieve a full octet of eight electrons, so these elements tend to form anions having -1 charges, known as halides.

In their elemental form, the halogens form diatomic molecules, X₂, connected by single bonds.  Since all of the halogens have one unpaired electron in their atomic forms, it is easy for them to "pair up" to form diatomic molecules.  The X₂ molecules are nonpolar, so the only interactions between them are fairly weak London forces, but as the size of the atoms increases, the London forces become stronger, increasing their melting and boiling points

Going down the group, regular ⬆️ in

1.  melting point & boiling point - caused by the increase in van der Waals forces (London dispersion force)

2. colour intensity ( become darker from colourless to yellowish green to reddish brown then purple)

3. atomic radius & ionic radius

4. density of the elements

Going down the group, regular ⬇️ in

1. Ionization energy

2. Electronegativity

3. Oxidising power (E°SRP)

Fluorine

a colourless gas

🧪Preparation (Industrial)

1. by the electrolysis of a solution of potassium fluoride in anhydrous hydrofluoric acid

Uses

1. used as a fluorinating agent for organic compounds

Chlorine

Yellowish green gas

🧪Preparation

1. By electrolysis molten sodium chloride in Down cell which also produces metallic sodium; chlorine is evolved at the anode

2.  Electrolysis of brine in Kellner-Solvay  method or using Chlor-alkali cell (Hydrogen is generated at the cathode and chlorine at the anode)

Uses

1. Water treatment

2. Production in the paper product

3. Food seasoning

4. Household Disinfectant (household chlorine bleach)

5. Manufacture of organic and inorganic chemicals

Bromine

Reddish-brown liquid

🧪Preparation

1.  Reacting the bromide ion with chlorine

2. Directly oxidising bromide with manganese dioxide

Uses

1. Mainly utilized in the manufacture of organic chemical

Chemical Properties
1. Displacement reactions

(a more reactive element will displace a less reactive one)
2. Reaction with H₂S
3. Reactions with water

(**Except for fluorine, all the halogens react with water in a disproportionation reaction)
4. Reaction with metal
(The halogens react with metals to produce salts)

5.  Reactions with non-metallic element
(Halogens form covalent bonds in compounds with non-metallic element )
6.  Reactions with alkali solution
7. Reaction with Hydrogen
(All halogens react with hydrogen and produce acidic hydrogen halides)
8. Reaction with Oxygen
(Halogens react with oxygen to form oxides)

Tests to identify halide ions

1. Add concentrated H₂SO₄ and heat

2. Add AgNO₃(aq), followed by NH₃(aq)

3. Add Cl₂(aq) or acidic NaClO(aq) and then CCl₄ (l)

COMPOUNDS OF HALOGEN

 Hydrogen Halides (HX)

HF

🧪Preparation

manufactured industrially by the reaction of fluorspar, CaF2, with sulphuric acid at 200-350℃

Uses

1. used for etching glass and metal

2. used to make refrigerants

3. Pickling stainless steel

HCl, HBr, HI

🧪Preparation

1.  direct reaction of hydrogen and halogen

2. reaction of phosphoric acid (a poor oxidizing agent) with halide salts in the presence of P₂O₅

3.  Reaction of halide salt with concentrated sulfuric acid (* Not suitable for HBr and HI)

Uses

1. HCl: cleaning, pickling, electroplating metals, tanning leather, and refining and producing a wide variety of products

2. HBr:  to make chemicals and drugs, as a solvent and as a veterinary drug

3. HI:  as a reducing agent and an analytical reagent. It is also used in the manufacturing of pharmaceuticals, disinfectants

Thermal stability of HX:
HF>HCl>HBr>HI
Acid strength of HX:
HF <HCl <HBr<HI

 Oxoacid of Halogen

Halogens generally form four series of oxoacids:

1. Hypohalous acids, HOX (+1 oxidation state)

2. Halous acids, HOXO (+3 oxidation state),

3. Halic acids, HOXO₂ (+5 oxidation state)

4. Perhalic acids, HOXO₃ (+7 oxidation state)

** Acid strength of oxoacid of chlorine is: HOCl < HOClO < HOClO₂ < HOClO₃

Hypohalous acids:

🧪Preparation

Hydrolysis of halogen(disproportionation reaction) Chlorine, bromine and iodine are slightly soluble in water
🧪 strength of the acids
HOCl> HOBr> HOI

Halous acids:

🧪Preparation
Chlorous acid is prepared by reaction of chlorine dioxide with hydrogen peroxide in the presence of barium hydroxide. The barium chlorite precipitated is then reacted with sulfuric acid to release chlorous acid

Halic acids:

🧪Preparation

Only HOIO₂ (iodic acid) can easily be prepared and isolated from its aqueous solution (prepared by reaction of iodine with nitric acid)

Perhalic acids:

🧪Preparation
HOClO₃ (perchloric acid) and HOIO₃ (periodic acid) can be prepared from the catalytic oxidation of the corresponding halate, XO₃ ⁻ followed by the addition of a strong acid

 Oxyanion and salts of halogen

1. Hypochlorous acid, ClO⁻ hypochlorite ion (+1 oxidation state)

2. Chlorous acid, ClO₂⁻ chlorite ion (+3oxidation state)

3. Chloric acid, ClO₃⁻ chlorate ion (+5oxidation state)

4. Perchloric acid, ClO₄⁻ perchlorate ion (+7oxidation state)

Hypochlorite ion (Oxidation State +1）
🧪Preparation

1. Electrolysis of cold (15 °C) brine (Chlor-alkali industry)

2. Reaction of CaO or Ca(OH)₂ with chlorine

Halite ion (Oxidation State +3）
(sodium chlorite, NaClO₂)
🧪Preparation

1.  reaction of ClO₂ with NaOH and H₂O₂

Halate ion (Oxidation State +5）
🧪Preparation
Electrolysis of hot (70 °C) brine

 Oxides of Halogen

1. Dichlorine hexoxide, Cl₂O₆

highly unstable molecule

mixture of anhydride of chloric and perchloric acid, ClO₂ +ClO₄⁻

2. Dichlorine heptoxide, Cl₂O₇
🧪Preparation
carefully dehydrating concentrated perchloric acid with P₂O₅ and distilling the product at –35 °C under 1mm Hg pressure

3. Diiodine pentoxide, I₂O₅,

white solid compound

decomposes only at temperature higher than 300 °C

As a powerful oxidizing agent, it will quantitatively convert CO to CO₂

🧪Preparation
dehydrating iodic acid at 200 °C in a stream of dry air

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Group VIIA
- 7 valence electron
- Diatomic molecules, X2

Down the group:
-Increase in:

melting point

colour intensity

atomic & ionic radius

density

-Decrease in:

ionization energy

electronegativity

oxidizing power

Industrial preparation
a)Flourine

-Obtain by an electrolysis of HF dissolved in molten KF

b)Chlorine
- Electrolysis of molten NaCl in Down Cells
- Electrolysis of brine in kellner-solvay method or using chlor-alkali cell

c)Bromine
-By passing chlorine gas into conc. sea water

Laboratory preparation

1. reacting a solution of halide ions with any substance that is strong oxidizing agent.

2. Reaction of metal halide with strong oxidizing agent in presence of acid.

Application of Halogen

1. Flourine:
-As agent for organic compound

2.Chlorine:
-In manufacturing of organic and inorganic chemicals in paper and pulp indusrty
-In water treatment
-In cleaning & sanitation

3. Bromine:
-Utilized in the manufacture of fuel additives, flame retardants, plants protection agents
-In manufacture of organic molecule

Chemical properties
-oxidizing agent
-react with H₂S
-react with water (except F₂)
-react with alkali solution
-react with non-metallic elements
-react with metal

Compound of Halogen

-Oxoacid of Halogen
-Hydrogen Halides
Oxyanion and salts of halogen

Oxoacid
-HXO, Hypohalous acid, +1
-HOXO3, Perhalic acid, +7
-HOXO, Halous acid, +3
-HOXO2, Halic acid, +5

Oxyanion And Salts of Halogen
- Compund of HX: HF, HCl, HBr, HI
-Acid Strength: HI>HBr>HCl>HF
-Thermal Stability: HF>HCl>HBr>HI

Hydrogen Halides
Laboratory preparation:

- Reaction of halide salts with conc. H2SO4
It is not suitable for preparation of HBr and HI because some of the hydride will be oxidize by the acid

- reaction of phosphoric acid with halides salts in the presence of P2O5

Uses:  In the manufacture of aluminum fluoride, boron trifluoride

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Halogen (Group VIIA)
- has 7 valence electron
-  has form singly bonded diatomic molecules X2

When going down the group:
-melting and boiling point increase
- colour intensity increase
- atomic and ionic radius  increase
-density increase
but decrease in
- ionization energy
-electronegativity
- oxidizing power

Industrial Preparation
Flourine - Electrolysis of HF dissolved in molten KF
Chlorine -
Electrolysis of molten NaCl in Down Cell
Electrolysis of brine in Kellner - Solvay method
Bromine - by passing chlorine gas into conc. sea water

Laboratory preparation
- Reacting a solution of the halide ions with any substance that is strong oxidizing agent
- Reaction of metal halide with strong oxidizing agent in presence of acid

Application
- Fluorine
as fluoring agent for organic compunds
-Chlorine
in manufacture of organic and inorganic chemicals in paper and pulp industry, in water treatment, in cleaning and sanitation
-Bromine
utilized in the manufacture of fuel additives, flame retardants , plants protection agents
in manufacture of organic molecule

Chemical properties
- Displacement reaction
- Reaction with H2S
- Reaction with water
- Reaction with alkali solution
- Reaction with non-metallic elements
- Reaction with metals

Physical properties
-Thermal stability
HF>HCL> HBr> HI
-Acid strength
HF<HCL<HBr<HI

Oxoacid
- Hypohalous acid, HXO ( +1)
- Halous acid , HOXO (+3)
- Halic acid , HOXO2 (+5)
- Perhalic acid , HOXO3 (+7)
* Acid strength of oxoacid
HOX< HOXO< HOXO2< HOXO3

Oxyanion
- ite (+1, +3)
- ate (+5, +7)
- hypo ( lowest)
- per (highest)

Preparation
Hypochlorite ion (+1)
- Electrplysis of cold (15 C ) brine (Chlor-alkali industry)
- Reaction of Cao or Ca(OH)2 with chlorine
Halite ion (+3)
- The salts are produced by reaction of ClO2 with NaOH and H2O2
Halite ion (+5)
- Electrolysis of hot (70C) brine

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Summary for Group VIIA

Halogen

7 valence electrons (ns²np⁵)

Diatomic molecules, X₂

Increases going down the group:

-M.p & b.p (↑ in Van der Waals forces)

-Colour intensity

-Atomic radius & ionic radius

-density

Decreases down the group

-I.E.

-Electronegativity

-Oxidizing power

F only have oxidation state of -1 due to it has the highest electronegativity.

Industrial Preparation

1. Fluorine : Electrolysis of HF dissolved in molten

2. Chlorine : Electrolysis in

(i) Down Cell (using molten NaCl)

(ii) Kellner-Solvay methods ( using brine or conc. NaCl ) / using Chor-alkali cell

1. Bromine :  Extracted by passing chlorine gas into conc. sea  water.

Laboratory Preparation

(i) Reacting a solution of the halide ions with any substance  that is a stronger oxidizing agent.

(ii) Reaction of metal halides, MX, with strong oxidizing agent  such as MnO2 in the presence of acid (e.g. H2SO4)

Application of Elemental Halogen

1. Fluorine : Mainly used as fluorinating agent for organic compounds.

2. Chlorine :

- In paper and pulp industry (to bleach the pigment)

- In water treatment

- In cleaning & sanitation
3. Bromine : Mainly utilized in the manufacture of organic chemicals.

Chemical Properties

- As oxidizing agent ( due to high electronegativity), oxidizing power ↓ down the group ( F2 > Cl2 > Br2 > I2 )
- Displacement reaction
- Reaction with H₂S
- Reaction with water(exception of fluorine)
- Reactions with alkali solution
- Reactions with non-metallic elements
- Reactions with metals

Tests to identify halide ions

1. Add conc.H2SO4 and heat

2. Add AgNO3(aq), followed by NH3(aq)

3. Add Cl2(aq) or acidic NaClO(aq) and then CCl4(l)

Compounds of Halogen

1.Hydrogen Halides (HX)

Industrial preparation : reaction of fluorspar  (acidspar), CaF2, with at 200 – 350 °C.

Laboratory preparation :

-Reaction of halide salts with conc. H₂SO₄ (not suitable for the preparation of  HBr and HI because some of the hydride will be oxidized by the acid )

- Reaction of H₃PO₄ (a poor oxidizing  agent) with halide salts in the presence of P₂O₅ .

Thermal stability of HX: HF > HCl > HBr > HI

Acid strength of HX: HF < HCl < HBr < HI

Strength as reducing agent: HCl < HBr < HI

2. Oxoacid of Halogen

-Cl, Br and I form 4 types of oxoacid.

-Fluorine form only 1 (hypofluorous acid, HOF)  because of its extreme difficulty to oxidize it.

(i) Hypohalous acid, HXO (+1)

-Preparation : Hydrolysis of halogen (disproportionation reaction)

-weak acid ( strength of acids: HOCl > HOBr > HOI

-oxidizing agents

-Industrial preparation of HOCl is by hydrolysis of dichlorine oxide, Cl2O

(ii) Halous acid, HOXO (+3)

- HOClO (more  stable) than

- prepared by reaction of ClO2 with H2O2 in the presence of Ba(OH)2. The barium chlorite, Ba(ClO2)2 precipitated is then reacted  with H2SO4 to release HOClO

(iii) Halic acid, HOXO₂ (+5)

- Only HOIO2 can easily be prepared and isolated from its aqueous solution. It is prepared by reaction of I₂ with HNO₃.

(iv) Perhalic acid, HOXO₃ (+7)

- HOClO3 & HOIO3 can be  prepared from the catalytic oxidation of the corresponding  halate, XO3−followed by the addition of a strong acid .

- strong acid and powerful oxidizing  agent.

The acid strength of oxoacid of halogen is: HOX < HOXO < HOXO2 < HOXO3 due to

-Oxygen is very electronegative, has strong tendency to pull electron density from any atom to which it is attached. The more lone oxygen attached to the central atom, the more polar will be the O-H bond and the easier the hydrogen atom will be released as H+, thereby increases the acidity of the acid.

3. Oxyanion and salts of halogen

-hypo- lowest oxidation no.

-per- highest oxidation number

Hypochlorite ion (+1) and its salt

-Preparation :

(a) Electrolysis of cold (15 °C) brine (Chlor-alkali industry)

The chlorine gas produced at anode is allowed to mixed  with hydroxide ion generated at cathode

(b) Reaction of CaO or Ca(OH)2 with chlorine

-Hypohalite ion in aqueous solution will undergo  disproportionate reaction

- The rate of reactions are ClO−< BrO− <IO−.

- Hypobromite salt is very unstable and hypoiodite ion does not exist in solution.

- Hypochlorite salt is used as a bleaching agent, oxidizing agent and disinfectants.

Halite ion (+3) and its salts

- Preparation : reaction of ClO2 with NaOH and  H2O2.

- The salts are used as bleaching and oxidizing agent. It is  also used as a deodorizing agent of odorous industrial  emission.

Halate ion (+5) and its salts

- Preparations

1. Electrolysis of hot (70 °C) brine.

2. Oxidation of halide ion (-1) by hypochlorite ion (+1).  This method is applicable for preparation of bromate  and iodate salt.

Oxides of Halogen

1.  Dichlorine hexoxide, Cl2O6

- highly unstable red molecule.

- mixture of anhydride of chloric and perchloric acid, ClO2+ClO4- (in solid phase)
2. Dichlorine heptoxide, Cl2O7

- prepared by carefully dehydrating  conc. perchloric acid with P2O5 and distilling the product at –35 °C  under 1mm Hg pressure.
3. Diiodine pentoxide, I2O5

- white solid compound

- decomposes only at temperature higher than 300 °C

- prepared by dehydrating iodic acid  at 200 °C in a stream of dry air.

- powerful oxidizing agent ( convert CO into CO₂)

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MOHAMAD SALMAN BIN MOHAMAD SABRI (A21SC0136)

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MOHAMAD SALMAN BIN MOHAMAD SABRI (A21SC0136)

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Group VIIA(Halogen)

-"Hals"-salt,"gennan"-generate.
-found as salts of the halide ion-high         reactivity.
-has 7 valence electrons (ns2np5)
-form singly bonded diatomic molecules,X2-only need one more electron to achieve stable octet electron arrangement.

Going down the group

Increase in ;
- melting & boiling point
- color intensity
- atomic & ionic radius
- density of the elements (F
Decrease in;
- ionization energy
- electronegativity
- oxidizing power

FLOURINE
-has highest electronegativity, its e. configuration is 1s2 2s2 2p5 and needs 1e. to fulfil octet.
-It can easily remove an electron from a nearby atom. Fluorine is isoelectronic with noble gas
-Obtain by an electrolysis of HF dissolved In molten KF. Pure HF is non conducting (non electrolyte) molecular compound.

Reaction :
-   2F- à F2 + 2e
-   2H+ + 2e à H2

Chorine
-Electrolysis of molten NaCl in Down cell
-Electrolysis of brine in kellner-solvay method or using chlor-alkali cell

Bromine
-extracted by passing chlorine gas into concentrated sea water

Laboratory preparation
1. reacting a solution of halide ions with substance that is a strong oxidizing agent
2. reaction of metal halide with strong oxidizing agent in presence of acid
3. Cl (made by oxidation of concentrated HCl with MnO2 or KMnO4)
4. solution of Cl2 in H2O obtain by reacting CaCl2. Ca(ClO)2 or NaOCl with HCl

Application of elemental halogen
Fluorine
- Fluorinating of organic & inorganic chemicals.
- In paper pulp industry (bleach pigment)
- In water treatment
- In cleaning and sanitation
Bromine
- Manufacture of organic chemicals
Chlorine
-in the manufacture of organic and inorganic chemicals, in paper and pulp industry, in water treatment, in cleaning and sanitation

Chemical Properties
-as an oxidizing agent (ability decrease from F2, Cl2, Br2, to I2)
-react with H2S
-react with water
(dissproportionation except F2)
-react with alkali solution
-react with non- metallic elements (form covalent bonds)
-react with metal

OXOACID
1.+ 7 ,HOXO3,Perhalic acid
2. +5,HOXO2,Halic acid
3. +3,HOXO,Halous acid
4. +1,HXO,Hypohalous acid

HXO
Preparation:
X2 + H2O —> H+ + X- + HOX
Properties:
-Weak acid ( HOCl >HOBr >HOI)
-Oxidizing agent

HOXO
-Only HOClO is important because more stable
Preparation:
Ba(OH)2 + H2O2 + 2ClO2 —> Ba(ClO2)2 + 2H2O + O2
Ba(ClO2)2 + H2SO4 —> BaSO4 + 2HClO2

HOXO2
-Only HOIO2 can easily prepared
Preparation:
I2+ 10HNO3 —> 2HOIO2 + 10NO2 + 4H2O

HOXO3
-Strong acid and powerful oxidizing agent
-HOClO3 and HOIO3 are prepared by the catalytic oxidation of the corresponding halate XO3- followed by adding strong acid

The number of lone oxygen atom attached to central atom affects the acidity of the oxoacids. Number of lone oxygens ↑, oxoacid becomes a better proton donor,

Acid strength of oxoacid oc chlorine :

HOCl < HOClO < HOClO2 < HOClO3

Oxyanion and salts of halogen
Hypochlorite ion (+1) and its salt
-Hypohalite ions in aq solution will undergo disproportionate reaction
-rate of reaction: ClO- < BrO- < IO-
Preparation

Electrolysis of cold (15°C) brine

Cl2 produced at anode is allowed to mix with OH- ions generated at cathode

Reaction of CaO/Ca(OH)2 with Cl2

Halite ion (+3) and its salts
-produced by reaction of ClO2 with NaOH and H2O2
-possible to convert mixture of chlorate (+1) & hypochlorite (+5) into a solution of chlorite (+3) ion.

Halate ion (+5) and its salts.
-Electrolysis of hot (70°C) brine
-Oxidation of X- ion (-1) by XO3- ion (+1) (bromate & iodate salts)

Perhalate ions and its salts.

1. Na, K, NH4+ perchlorates

2. NaClO4 is manufactured from NaClO3 by electrochemical synthesis.

3. K+ & NH4+ salts are produced by metathesis with NaClO4

Oxides of Halogen
-Cl2O6 is highly unstable red molecule
-Cl2O7 may be prepared by dehydrating conc. perchloric acid with P2O5 and distilling the product at -35°C under 1mm Hg pressure
-I2O5 is a white solid compound and decomposes only at T > 300°C. Produced by dehydrating iodic acid at 200°C in a stream of dry air.

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HALOGEN
▫ 7 valence electron
▫ singly bonded diatomic molecules, X2

Going down the grp

Increase:

m.p & b.p (Van der Waals forces increase)

colour intensity

atomic & ionic radius

density

Decrease:

I.E.

Electronegativity

Oxidizing power

Industrial preparation

-        Fluorine ( electrolysis of HF dissolved in molten KF)

-        Chlorine

(electrolysis of molten NaCl in Down Cell)

(electrolysis of brine in Kellner-Solvay method)

-        Bromine (by passing chlorine gas into conc. sea water)

Laboratory preparation

-        Reacting solution of halide ions with stronger oxidizing agent

-        Reaction of metal halide with strong oxidizing agent

-        Chlorine: oxidation of conc HCl with MnO₂ or KMnO4

Chemical properties:

-        As oxidizing agent - ability decrease down the grp (due to high electronegativity)

-        React with water – disproportion reaction (except F)

Tests to identify halide ions:

i.                 Add conc H₂SO₄ and heat

ii.                Add AgNO₃ followed by NH₃

iii.               Add Cl₂ or acidic NaClO and then CCl4

COMPOUNDS OF HALOGEN

1.      Hydrogen halides (HX)

Industrial preparation:

HF: reaction of CaF₂ with H₂SO₄

HX (X= Cl,Br,I) : reaction of H₂ and X₂

Laboratory preparation:

-        Reaction of halide salts with conc. H₂SO₄

(not suitable for HBr and HI – some of hydride will be oxidize by acid)

-        Reaction of phosphoric acid (poor oxidizing agent) with halide salts in presence of P₂O5

Thermal stability: HF > HCl > HBr > HI

Acid strength: HF << HCl < HBr < HI

Strength as reducing agent: HCl < HBr < HI

2.      Oxoacid of halogen

+7 : Perhalic acid (HOXO3)

+5 : Halic acid (HOXO2)

+3 : Halous acid (HOXO)

+1 : Hypohalous acid (HXO)

i.                 Hypohalous acid, HOX

-weak acid ( HOCl > HOBr > HOI )

-oxidizing agent

-industrial preparation : hydrolysis of dichlorine oxide,Cl₂O

ii.                Halous aicd, HOXO

HOClO (more stable) – prepared by reaction of chlorine dioxide with hydrogen peroxide in the presence of barium hydroxide. Barium chlorite ppt react with sulphuric acid release chlorous acid.

iii.               Halic acid, HOXO₂

HOIO₂ (iodic acid) – prepared by reaction of iodine with nitric acid

iv.               Perhalic acid, HOXO₃

-HOClO3 and HOIO3- prepared by catalytic oxidation of corresponding halite, XO3- followed by addition of strong acid.

- strong acid and powerful oxidizing agent

Acid strength of oxoacid of chlorine:

HOCl < HOClO < HOClO₂ < HOClO3

Oxides of halogen:

Dichlorine hexoxide, Cl₂O₆

-highly unstable

-mixture of anhydride of chloric acid and perchloric acid

Dichlorine heptoxide, Cl₂O₇

-prepared by dehydrating conc. perchloric acid with P2O5 and distilling the product at -35◦C under 1mmHg pressure

Diiodine pentoxide, I₂O₅

-only decompose at temp higher than 300◦C

-prepared by dehydrating iodic acid at 200◦C in a stream of dry air

- powerful oxidizing agent (convert CO to CO₂)

# data[].attributes.headline
Muhammad Aiman Aqil bin Muhamad Eri (A21SC0147) 

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Muhammad Aiman Aqil bin Muhamad Eri (A21SC0147) 

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Summary of Group VIIA (Halogen)

7 valence electrons

ns²np⁵

Diatomic molecules, X₂

Down the group:

-Increases in:

Atomic & Ionic radius

Melting & boiling point

Colour intensity

Density

-Decreases in:

IE

Electronegativity

Oxidizing power

Industrial preparation
-Fluorine

Electrolysis of HF dissolved in molten KF

-Chlorine

Electrolysis of molten NaCl in Down cell

Electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell

-Bromine

By passing chlorine gas into concentrated seawater

Laboratory preparation

By reacting a solution of the halide ions with any substance that is a stronger oxidizing agent

(Chlorine) by oxidation of concentrated HCl with MnO₂ or KMnO₄

A solution of Cl₂ in water is readily obtained by reacting bleaching powder, CaCl₂.Ca(ClO)₂ or bleaching solution, NaOCl with HCl

Tests to identify halide ions, (CL⁻ Br⁻ I⁻)

Adding concentrated H₂SO₄ and heat

Adding AgNO₃ (aq), followed by NH₃ (aq)

Adding Cl₂ (aq) or acidic NaClO(aq) and then CCl₄ (l)

Compounds
-Hydrogen Halides, HX

HF, HCl, HBr, HI

Thermal stability: HF>HCl>HBr>HI

Acid strength : HI>HBr>HCl>HF

-Oxoacid

Hypohalous acid, HXO, +1

Halous acid, HOXO,  +3

Halic acid, HOXO₂,+5

Perhalic acid, HOXO₃, +7

Acid strength: HOX<HOXO<HOXO₂<HOXO₃

-Oxyanion and salts

HClO, Hypochlorous acid, +1

HOClO, Chlorous acid, +3

HOClO₂, Chloric acid, +5

HOClO₃, Perchloric acid, +7

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GVIIA - Halogen
- ns²np⁵
-7 v.e
- form singly bonded diatomic molecules, X₂

Going down the group,
increase in:
- m.p and b.p (due to increase in Van der Waals forces)
- color intensity

so physical state of halogen at r.t is
F - colorless gas
Cl - yellowish-green gas
Br - reddish-brown liquid
I - violet solid
At - solid

- density
- atomic and ionic radii
decrease in:
- I.E
- electronegativity
- oxidizing power, E°SRP

F only 1 oxidation state (-1) due to:
- high electronegativity
- 1 more electron to fulfill octet

Industrial preparation:
Fluorine:
a) Electrolysis of HF dissolved in KF solution
- KF act as electrolyte
- reaction:

anode: 2F⁻ -> F ₂ + 2e
cathode: 2H⁺ + 2e -> H ₂

Chlorine:
a) Electrolysis of NaCl in down cell (high T)
- reaction:

graphite anode: 2Cl⁻ -> Cl ₂ + 2e
cylindrical cathode: 2Na⁺ + 2e -> 2NaCl

b) Electrolysis of brine in Kellner-Solvay method / using Chlor-alkali cell

Bromine:
a) Sea water passing Cl₂ gas

Cl ₂(g) + 2Br⁻(aq) -> 2Cl⁻(aq) + Br ₂(g)

when air pass through sea water, vaporize Br2 and transfer the gas into sulfite solution.

Br ₂ + SO ₃ ²⁻ -> 2Br⁻ + SO ₄ ²⁻

Cl ₂ gas is used to oxidize Br⁻ ion back to Br ₂ molecule b4 distilling the pure Br ₂ out

Lab Preparation
1) Halide ions with stronger O.A
Bromine : 2Br⁻(aq) + Cl₂(g)-> Br₂(g) + 2Cl(aq)
2) Metal Halide with stronger (presence of acid)
4MX + 4H₂SO₄ + MnO₂ -> 4MnSO₄ + MnX₂ + 2H₂O + X2
(M= Na,K) (X= Cl, Br, I)
3) Oxidation of conc HCl with MnO2/KMnO4 (Chlorine only)

MnO ₂(aq) + 2Cl⁻(aq) + 4H+(aq) -> Mn ²⁺(aq) + Cl ₂(g) + 2H ₂ O(l)2MnO ⁴⁻(aq) + 16H⁺(aq) + 10Cl⁻(aq) -> 2Mn ²⁺(aq) + 5Cl ₂(g) + 4H ₂ O(l)

4) Solution of Cl ₂ in water.
- bleaching powder (CaCl₂∙Ca(ClO₂)) with HCl

CaCl ₂∙Ca(ClO ₂)(s) + 4H⁺(aq) + 2Cl⁻(aq) -> Ca ²⁺(aq) + H2O(l) + Cl ₂(aq)

- bleaching solution NaOCl

2HCl(aq) + NaOCl(aq) -> NaCl(aq) + H ₂ O(l) + Cl ₂(aq)

Application of elemental halogen
Fluorine
- Fluorinating of organic & inorganic chemicals.
- In paper pulp industry (bleach pigment)
- In water treatment
- In cleaning and sanitation
Bromine
- Manufacture of organic chemicals

Chemical Properties
- O.A
due to halogen's high electronegativity
a) displacement reaction (ability of O.A decrease going down the group)

Hence, only halogen at higher position can displace halogen at lower position in periodic table.

b) reaction with H ₂ S

X₂(g) + H₂S -> 2HX(aq) + S(s) (X=Cl, Br, I)

Reaction with water

disproportionation reaction (except F₂)

X₂(g)(+0) + H₂O(l) ⇋ HOX(aq)(+1) + H⁺(aq) + X⁻(aq)(-1) (X= Cl, Br, I)

only F₂ and O₂ can oxidize water

2F₂(g) + 2H₂O(l) -> 4HF(aq) + O₂(g)
Cl₂(g) + H₂O(l) ⇌ HOCl(aq) + H⁺(aq) + Cl⁻(aq)

In presence of light, HOCl will decompose

2HOCl(aq) ⇌ 2H⁺(aq) + 2Cl⁻(aq) + O₂(g)
Reactions with alkali solution
General disproportionation reaction for
X= Cl, Br, I

X₂(g) + 2OH⁻(aq) -> X⁻(aq) + XO⁻(aq) + H₂O(l)

Hypohalite, XO⁻ tends to disproportionate further

3XO⁻(aq)(+1) -> 2X⁻(aq)(-1) + XO₃⁻(aq)(+5)

Reactions with non-metallic elements

halogens form covalent bonds in compounds

the compounds formed is interhalogen compounds.

aq solution of non-metal halides undergo hydrolysis reactions

Reactions with metals

halides of s-block elements are ionic

neutral in aq solutions

MX₂ (M= Be & Mg, X= Cl, Br, I) have some covalent character.

halides of p-block and d-block metals in low/high oxidation stable are ionic/show some covalent.

Tests to identify halide ions

1. heat with conc. H₂SO₄

2. AgNO₃ + NH₃

3. Cl₂/acidic NaClO(aq) + CCl₄(l)

COMPOUNDS OF HALOGEN
Halogen Halide (HX) - hydride of halogen
HF
Industrial Preparation

Fluospar (acidspar), CaF2, with H2SO4 at 200°C - 350°C

HCl, HBr, HI
- prepared by direct reaction of H₂ & X2

Lab Preparation of HX

Halide salts + conc H₂SO₄

not suitable as some of the hydride will be oxidize by acid.

H₃PO₄ + Halide salts (presence of P₂O₅)

Physical properties of HX
When going down the group,

Thermal stability decrease
Acid strength increase
- due to high electronegativity difference in H-F bonds.

Chemical properties of HX

Reacts with metals above hydrogen in electrochemical series.

Reacts with metal oxides, hydroxides & carbonates.

2HF + SiO₂ -> H₂SiF₆ + 2H₂O

HX as reducing agent (HCl < HBr < HI)

Oxoacid

Cl, Br, I form types of oxoacid

F form only HOF due to its extreme difficulty to oxidize it.

Preparation
1. Hypohalous Acid, HOX (+1)

hydrolysis of halogen: disproportionation reaction

weak acid. acid strength: HOCl > HOBr > HOI

Oxidizing agents

Industrial preparation of HOCl

by hydrolysis of dichlorine oxide, Cl2O

2. Halour Acid, HOXO (+3)

Only chlorous acid, HOClO stable

HOClO prepared by

Cl₂ with H₂O₂ in the presence of Ba(OH)₂. Ba(ClO₂)₂ ppted is then react with H₂SO₄ to release HOClO

3. Halic Acid, HOXO₂ (+5)

prepared by isolated from its aq solution

reaction of I₂ with HNO₃

4. Perhalic Acid, HOXO₃ (+7)

prepared from catalytic oxidation of halate, XO₃⁻ followed by addition of strong acid.(X= Cl, I)

Effect of the no. of O ₂ on the acidity of oxoacids
no. of lone O₂ bonded to the central atom ↑, more polar the O-H bond, oxoacid becomes a better proton donor, acid strength ↑

Oxyanion and salts of halogen
Hypochlorite ion (+1) and its salt

Hypohalite ions in aq solution will undergo disproportionate reaction

rate of reaction: ClO- < BrO- < IO-

Hence, HBrO and HIO doesn't exist as they are very unstable or evenly do not exist.

Preparation

Electrolysis of cold (15°C) brine

Cl₂ produced at anode is allowed to mix with OH- ions generated at cathode

Reaction of CaO/Ca(OH)₂ with Cl₂

Halite ion (+3) and its salts

produced by reaction of ClO2 with NaOH and H2O2

possible to convert mixture of chlorate (+1) & hypochlorite (+5) into a solution of chlorite (+3) ion.

Halate ion (+5) and its salts.
Preparations:

Electrolysis of hot (70°C) brine

Oxidation of X⁻ ion (-1) by XO₃⁻ ion (+1) (bromate & iodate salts)

Perhalate ions and its salts.

Na, K, NH₄⁺ perchlorates ✔

NaClO₄ is manufactured from NaClO₃ by electrochemical synthesis.

K⁺ & NH₄⁺ salts are produced by metathesis with NaClO₄.

Oxides of Halogen

Cl₂O₆ is highly unstable red molecule

Cl₂O₇ may be prepared by dehydrating conc. perchloric acid with P₂O₅ and distilling the product at -35°C under 1mm Hg pressure

I₂O₅ is a white solid compound and decomposes only at T > 300°C. Produced by dehydrating iodic acid at 200°C in a stream of dry air.

a powerful oxidizing agent

can estimate I₂ liberated by Na₂S₂O₃ to allow quantitative determination of CO

# data[].attributes.headline
NURHASYIMAH BINTI MOHD HARIS (A21SC0278)

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NURHASYIMAH BINTI MOHD HARIS (A21SC0278)

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Know as the halogen because
-  Can be found as salts of the halide ion because of their high reactivity;
- Have 7 electron  and form singly bonded diatomic molecules, X2-

Physicochemical Properties of elements
( Increase down the group )
-  Melting and boiling point, colour intensity, atomic and ionic radius and density

( Decrease down the group )
-  Ionization energy, electronegativity and oxidizing power

Chemical Properties
- halogen as a good oxidizing agent
(high electronegativity of halogen)
a) Displacement reaction
b) Reaction with H₂S
c) Reactions with water (disproportionate reaction except fluorine)
d) Reactions with alkali solution (form halide ion + hypohalite + water) (disproportionate reaction except fluorine)
e) Reactions with non-metallic elements (form covalent bond)
f) Reactions with metals

Oxides of Halogen
Cl₂O₆
• highly unstable red molecules
• preparation : anhydride chloric + perchloric acid, ClO₂+ & ClO₄-

Cl₂O₇
• dehydrating concentrated perchloric acid with P2O5 and distilling (-35C, 1 mm Hg pressure)

I₂O₅
• white solid
• decompose at temperature > 300°C
• preparation : dehydrating ionic acid at 200°C in a steam of dry air

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S U M M A R Y  O F
H A L O GEN

DOWN THE GROUP , REGULAR INCRREASE IN....
- melting and boiling point
- colour intensity
- atomic and ionic radius
- density of the element

DOWN THE GROUP , REGULAR DECREASE IN....
- IE
- electronegativity
-oxidizing power

Industrial Preparation

Fluorine - electrolysis of HF dissolved in molten KF.
Chlorine - i) electrolysis of molten NaCl in
Down Cell.
ii)  Electrolysis of brine in Kellner-
Solvey method  or using Chlor-
alkali cell.
Bromine -  Extracted by passing  chlorine gas into concentrated sea water.

APPLICATION OF HALOGEN

Fluorine :
- Mainly used as fluorinating agent for organic compounds.
Chlorine :
- In water treatment
- In cleaning and sanitation
- used in manufacture organic and inorganic chemicals.
Bromine :
- Mainly utilized in the manufacture of organic chemicals such as fuel additives
(1,2-dibromoethane ).

CHEMICAL PROPERTIES

1. Halogen as oxidizing agent (oxidizing power decrease down the group)
2. Reaction with water
X2 (g) + H2O(l) HOX(aq) + H+ (aq) + X− (aq) (X = Cl, Br, I)

only F2 and Cl2 can oxidise water

3. Reaction with alkali solution
X2 (g) + 2OH− (aq) → X− (aq) + XO− (aq) + H2O(l) (X=Cl, Br, I)

4. Reaction with non metallic elements
- they tends to form covalent bond.

Tests to identify halide ions
(Cl-, Br-, I-)
a. Add conc.H2SO4 and heat
b. Add AgNO3 (aq), followed by NH3 (aq )
c. Add Cl2 (aq) or acidic NaClO(aq) and then CCl4 (l)

Physical properties of halogen halides
a. thermal stability decrease down the group
b. strength of acidity increase down the group

OXOACIDS OF HALOGEN
1.  Perhalic acid  (HOXO3) , +7
2. Halic acid (HOXO2) , +5
3. Halous acid (HOXO) , +3
4. Hypohalous acid  (HOX) , +1

per-highest oxidation no.
hypo-lowest oxidation no.

Oxyanion and salts of halogen
1. HClO (+1) - Hypochlorous acid
2. HOClO (+3) - Chlorous acid
3. HOClO2 (+5) - Chloric acid
4.  HOClO3 (+7) - Perchloric acid

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Introduction
-found as salts of the halide ion-high reactivity
-has 7 valence electrons (ns²np⁵)
-form singly bonded diatomic molecules,X₂ –(only need one more electron to achieve stable octet electron arrangement)

Increase going down the group(F<Cl<Br<l<At)
-melting point
- boiling point
- atomic radius and ionic radius
-density
Decrease going down the group

1. ionization energy

2. electronegativity

Anomaly of F
-has 1 oxidation state(has highest electronegativity)

Industrial preparation
Fluorine
-Obtained by an of HF dissolved in molten KF
-The KF in the mixture serves as an electrolyte because pure HF is (non-electrolyte) molecular compound.

Chlorine
-Electrolysis of molten NaCl in down cell
-Electrolysis of brine in method or using Chlor-alkali cell

Bromine
-Extracted by passing into concentrated sea water

Laboratory Preparation
-Reacting a solution of the halide ions with any substance that is stronger oxidizing agent.
-Reaction of metal halide with strong oxidizing agent such as MnO2 in the presence of acid.

Application
Fluorine
-Mainly used as fluorinating agent for organic compounds.
Chlorine
-in water treatment

COMPOUND OF HALOGEN
1..Oxoacid of Halogen
2.Hydrogen Halides (HX)
3.Oxyanion and salts of halogen

Oxoacid
HXO, Hypohalous acid, +1
HOXO3, Perhalic acid, +7
HOXO, Halous acid, +3
HOXO2 , Halic acid, +5

OXYANION AND SALTS OF HALOGEN
Compound of HX: HF, HCl, HBr,HI
Acid strength : HI>HBr>HCl>HF
Thermal stability : HF>HCl>HBr>HI

Hidrogen Halides

Laboratory preparation

- Reaction of halide salts with conc. H2SO4
It is not suitable for preparation of HBr and HI because some of the hydride will be oxidize by the acid

- reaction of phosphoric acid with halides salts in the presence of P2O5

Uses:  In the manufacture of aluminum fluoride, boron trifluoride

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Halogen
- 7 valence electrons
- diatomic molecules, X₂

Regular increase in
-melting point & boiling point (increase in Van der Waals forces)
-colour intensity
-atomic radius & ionic radius
-density
Regular decrease in
-ionization energy
-electronegativity
-oxidizing power

F only has 1 oxidation state (-1) because
-has the highest electronegativity
-easily remove an electron from a nearby atom

Preparation of fluorine
-electrolysis of HF dissolved in molten KF
-KF as an electrolyte because pure KF is non-conducting molecular compund

Preparation of Chlorine (electrolysis)
-Downs Cell
*molten/ fused NaCl
*extremely high temperature
-Kellner-Solvay/ Chlor-alkali cell (industrial process)
*brine or conc. NaCl
*room temp.

Preparation of Bromine
-passing through chlorine gas into conc. sea water

Laboratory Preparation
1. solution of the halide ions + stronger oxidizing agent
2. metal halide + strong oxidizing agent (MnO₂ in acid)
For chlorine:
- Oxidation of conc. HCl with MnO₂/KMnO₄
-CaCl₂.Ca(ClO)₂/ NaOCl + HCl

Application
Fluorine- fluorinating agent for oarhanic compound
Chlorine- water treatment
Bromine- utilize in the manufacture of organic chemicals

Chemical properties
-oxidizing agent
*due to high electronegativity
*decrease down the group
*halogen only can oxidize halogen which is below it
-undergo disproportionation( except F₂) with water
(a reaction undergoes both oxidation and reduction to form two different product)

1. Reaction with water
2. Reaction with alkali solution
3.Reaction with non-metallic elements
4. Reaction with metals

Ionic halide:
-halides of s block
-low oxidation state
Covalent halide:
-halides of Be and Mg
-high oxidation state

Tests to identify halide ions
- add conc. H₂SO₄ and heat
- add AgNO₃ foolowed by NH₃
- add Cl₂/ acidic NaClO and then CCl₄

Hydrogen halide
-as reducing agent HCl<HBr<HI
Preparation
-CaF₂+H₂SO₄ for HF
-H₂+X₂ for HCl, HBr, HI

Laboratory preparation of HX
-halides salt+conc. H₂SO₄
*only for HCl due to HBr and HI will be oxidize by the acid
-halide salts + Phosphoric acid (poor oxidizing agent) ( suitable method)

Acid Strength: HF<<HCl<HBr<HI
-very high electronegativity difference in HF

1. Reaction with metal oxides, hydroxides, carbonates
2. Reaction with SiO₂
3. Reactions with metals above hrygen in the electrochemical Series

Oxoacids of Halogen
-oxyanions with ending -ite (+1, +3)
-oxyanions with ending -ate (+5, +7)
hypo- lowest oxidation no.
per- highest oxidation no.

+1- hypohalous acid, HXO
*hydrolysis of halogen
*oxidizing agent
-only hypochlorite ions & its salts are important
a. Electrolysis of cold brine
b. Reaction of CaO/Ca(OH)₂ with chlorine

+3- halous acid, HOXO
Ba(OH)₂+H₂O₂+2ClO₂→ Ba(ClO)₂+2H₂O+ O₂
Ba(ClO)₂+ H₂SO₄→BaSO₄+ 2HClO₂
-NaClO₂ is industrially important

+5- halic acid, HOXO₂
*only HOIO₂ can easily prepared by iodine+nitric acid
-electrolysis of hot brine

+7- perhalic acid, HOXO₃
*catalytic oxidation of corresponding halate ions followed by the addition of a strong acid
*strong acid &powerful oxidizing agent

Acid strength:
HXO< HOXO< HOXO₂< HOXO₃
due to:
- Oxygen is very electronegative element
-strong tendency to pull electron density away from any atom to which it is attached
-the more lone oxygen attached to the central atom, the more polar the O-H bond, the easier the hydrogen atom will be released, thus increase the acidity of the acid

Oxides of halogen
*Cl₂O₆
-unstable red molecule
-mixture of anhydride of chloric and perchloric acid.
*Cl₂O₇
-prepared by dehydrating conc. perchloric acid and distilling at -35º C under 1 mm Hg pressure
*I₂O₅
-white solid
-decompose only at temperature higher than 300º C
-prepared by dehydrating ionic acid at 200ºC in a stream of dry air

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NUR NABILA NATASYA BINTI MOHAMAD NAZRI  A21SC0247

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NUR NABILA NATASYA BINTI MOHAMAD NAZRI  A21SC0247

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HALOGEN

diatomic molecules

has 7 valance electron

Generally increase

melting and boiling point

color intensity

atomic and ionic radius

density

Generally decrease

IE

electronegativity

oxidizing power

Industrial Preparation

Chlorine

electrolysis of molten NaCl in Down Cell

Fluorine

electrolysis of HF dissolved in molten KF

Bromine

by passing chlorine gas into conc. sea water

Laboratory Preparation

reacting a solution of halide ion with strong oxidizing agent

reaction of metal halide with strong oxidizing agent with presence of acid

Application

Fluorine - as fluorinating agent

Chlorine- in manufacture of organic and inorganic chemical

Bromine- in manufacture of organic molecule

Compounds of Halogen (HX)

HF, HCl, HBr,HI

Thermal stability : HF>HCl>HBr>HI

Acid strength : HI>HBr>HCl>HF

Oxoacids of Halogen

HXO, Hypohalous acid, +1

HOXO, Halous acid, +3

HOXO2 , Halic acid, +5

HOXO3, Perhalic acid, +7

The acid strength : HOX<HOXO<HOXO2<HOXO3

- number of lone oxygen increases,         acidity increases

Oxyanions and salts

HClO, Hypochlorous acid, +1

HOClO, Chlorous acid, +3

HOClO2, Chloric acid, +5

HOClO3, Perchoric acid, +7

# data[].attributes.headline
NORIZATUL FILZA BINTI MUHAMAD PUZI (A21SC0205)

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NORIZATUL FILZA BINTI MUHAMAD PUZI (A21SC0205)

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summary halogen group VIIA

halogen is from the Greek word that is “Hals” = salt “Gennan” = generate

found as salts of halide ion bcs of their  high reactivity

each atom has 7 valence electron and need 1 electron to achieve noble gas configuration. So the elemental state they form singly bonded diatomic molecules X2.

going down the group :

- Regular increase in,

·  melting point & boiling point (bcs increase in van der waals forces)

· colour intensity

· atomic radius & ionic radius

· density of elements

·  F < Cl < Br < I < At

-  Regular decreases in,

· ionization energy

· electronegativity

· oxidizing power

FLOURINE

§  has highest electronegativity, its e. configuration is 1s2 2s2 2p5 and needs 1e. to fulfil octet.

§  It can easily remove an electron from a nearby atom. Fluorine is isoelectronic with noble gas

§  Obtain by an electrolysis of HF dissolved In molten KF. Pure HF is non conducting (non electrolyte) molecular compound.

§  Reaction :

-   2F- à F2 + 2e

-   2H+ + 2e à H2

CHLORINE

§  Electrolysis in molten NaCl in down cell

§  Electrolysis in Kellner-Solvay method or Chlor-alkali cell

§  Industrial process for electrolysis of NaCl

§  Technology used to produce chlorine and sodium hydroxide

BROMINE

§  Extracted by passing chlorine gas into concentrated sea water. The bromine ion oxidized to molecular bromine.

- Cl2(g) + 2Br-(aq) à Br2(g)

§  Air passed through the seawater to vapourize bromine and transfer gas into sulfite solution

§  Sulfite reduce bromine to bromine ion

- SO3 2- + Br2 à SO4 2- + 2Br-

§  Chlorine gas is used to oxidize the bromine ion to m,olecular bromine before distilling the pure bromine out.

LABORATORY PREPARATION

§  React solution of halide ions with any substance that is stronger oxidizing agent

§  Reaction of metal halide with strong oxidizing agent (MnO2) in presence of acid (H2SO4)

§  Chlorine can be made by oxidation of concentrated HCl with MnO2 or KMnO4

§  Solution of Cl2 in water is readily obtained by reacting bleaching powder, CaCl2.Ca(ClO)2 or bleaching solution, NaOCl with HCl

APPLICATION OR ELEMENT HALOGEN

§  Flourine

-  Mainly used as fluorinating agent for organic compounds

-  Used in polymers, refrigant fluids, aerosol propellants and nonflammable anesthetics

§  Chlorine

-  In manufacture of organic and inorganic chemicals

-  In paper and pulp industry (bleach)

-  Water treatment

-  Cleaning and sanitation

§  Bromine

- Mainly utilized in manufacture of organic chemicals

- Fuel additives (1,2-dibromoethane)

- Flame retardants (brominated diphenylether)

- Plants protection (methyl bromide)

- Fire extinguisher (bromodifluoromethane)

- Tear gases (bromoacetophenone)

- Inhalation anesthetics, dyes

Chemical properties

Halogen as oxidizing agent

Bcs o high electronegativity of halogen, they tend to gain electrons from other substance and serves as oxidizing agents.

Ø  Displacement reaction

- The ability of halogen as oxidizing agent decrease going down the group

- F2 > Cl2 > Br2 > I2

- F2 will oxidize Cl-, Br-, and I- ions

- Cl2 will oxidize Br- and I- ions

- Br2 will oxidizing I- ion

Ø  Reaction with H2S

- Lose hydrogen: oxidation

- Gain hydrogen: reduction

Reaction with water

- Reactants serve as oxidizing and reducing agents

- F2 and Cl2 can oxidize water

- 30% dissolved chlorine exists in form of HOCl and Cl-

- In presence of light HOCl will decompose

Reaction with alkali solution

- General disproportionation reaction for, X = Cl, Br and I

- The hypohalite, XO- tends to disproportionate further

Reactions with non-metallic elements

- Halogens form covalent bonds In compounds with non-metallic elements

- Aqueous solution of non-metal halides undergo hydrolysis reactions

Reactions with metals

- Halides of s-block metals are ionic (aqueous solution neutral)

- MX2 have some covalent character

- Halides d and p block metals in low oxidation state are ionic and high oxidation state show some covalent character

Compounds of halogen

Hydrogen Halides (HX) – Hydride of Halogen

o   Industrial preparation HF

- Manufactured industrially by reaction of fluorspar, CaF2 with sulfuric acid

o   Application of HF

- Manufacture of aluminum fluoride, boron trifluoride, uranium tetrafluoride and ammonium hydrogen fluoride

- In the manufacture of fluorohalogen hydrocarbons

- Pickling stainless steel

- Glass etching & polishing

- Semiconductor manufacture

Uses of HCl acid

· Pickling of metals

· Acid treatment of oil and gas wells

· Neutralization in inorganic and organic chemistry

· Hydrolysis of protein and carbohydrates

· Regeneration of ion-exchangers

· Manufacture of ClO2

Laboratory preparation of HX

- Reaction halide salts with conc. sulfuric acid

- This method not suits for preparation HBr and HI, hydride will oxidize by acid

- Suitable method, reaction of phosphoric acid with halide salts in presence of P2O5

Physical properties of hydrogen halide

- Thermal stability HX : HF > HCl > HBr > HI

- Acid strength of HX : HF << HCl < HBr < HI

- HF is weak acid bcs bond fluorine and hydrogen is very strong bcs very high electronegativity difference.

- Fluorine doesn’t let hydrogen go easily, needs more energy to break the bond.

- Extent of donating H+ is low in HF that why it is weak acid

Chemical properties of hydrogen halides

- Reacts with metal above hydrogen in electrochemical series

- Reacts with metal oxides, hydroxides and carbonates

- HF reacts with glass

- HX as reducing agent

- Strength as reducing agent : HCl < HBr < HI

# data[].attributes.body
Natural occurance of halogen

F – Fluorspar, cryolite, fluoroapatite

Cl – Rock salt

Br – Ocean

I – Chile Saltpetre

- Intoduction

Each atom has 7 valence e⁻

Form singly bonded diatomic molecules

- Proceed down the group,

M.p and B.p ↑

Colour intensity ↑

Atomic and ionic radius ↑

Density of elements ↑

- Proceed down the group,

Ionization energy ↓

Electronegativity ↓

Oxidising power ↓

Fluorine,

Highest electronegativity

Preparation :

Electrolysis of HF dissolved in molten KF

Uses : Refrigerant fluids

Chlorine

|   | Down Cell  | Kellner-Solvay methods
| Electrolyte used | Molten/used NaCl  | Brine or concentrated NaCl
| Side product | Na metal (in cathode) | H₂ gas and NaOH
| Reaction Condition | High temperature  | Normal/room temperature

Uses : Bleaching , water treatment , cleaning and sanitation

Bromine

Preparation :

1.     2Br⁻ + Cl₂ -> Br₂ + 2Cl⁻

2.     Reaction of metal halides with strong oxidizing agent in presence of acid

3.     Oxidation of conc HCl with MnO₂ or KMnO₄

4.     Reaction of CaCl₂·Ca(ClO)₂ or NaOCl with HCl

Uses : Manufacture of organic chemicals

CCl₄ does not hydrolyse because the C atom does not have d orbital to receive a pair of electron from water molecules.

| Tests  | Cl⁻ | Br⁻ | I⁻
| Add Conc H₂SO₄ and heat  | HCl gas released | HBr, SO₂, and Br₂ liberated   | SO₂, H₂S and I₂ liberated
| Add AgNO₃ followed by NH₃ | White precipitate dissolve in NH₃ | Yellowish-white ppt, dissolved in conc NH₃ | Yellow ppt, sparingly dissolved in conc NH₃
| Add Cl₂ or acidic NaClO and then CCl₄ | No reaction  | Br₂ released Brown CCl₄ layer formed  | I₂ released. Pink CCl₄ layer formed

HF:

CaF₂ + 2H₂SO₄ -> 2HF + Ca(HSO₄)₂  (200℃-500℃)

Uses : Pickling Stainless Steel

Weak acid :

Bond between H and F is strong, because of high electronegativity difference. F does not let hydrogen go easily, needs more energy to break the bond. The ability of HF to donate H⁺ ions are low.

HX : (X: Cl , Br , I )

1.     H₂ + X₂ -> 2HX

Use of HCl : pickling metals , Acid treatment of oil and gas wells

2.     Reaction of halide salts with conc. H₂SO₄ (not suitable for HBr and HI)

3.     Reaction of phosphoric acid with halide salts in presence of P₂O₅

Ability as reducing agent : HCl<HBr<HI

Oxoacids of halogen:

+7 : HOXO₃ : perhalic acid

prepared from the catalytic oxidation of the corresponding halate, XO3− followed by the addition of a strong acid.

HOCl < HOClO < HOClO₂ < HOClO₃

+5 : HOXO₂ : Halic acid

I2(aq) + 10HNO3(aq) → 2HOIO2(aq) + 10NO2(g) + 4H2O(l)

+3 : HOXO : Halous acid

Ba(OH)2 + H2O2 + 2ClO2 → Ba(ClO2)2 + 2H2O + O2

Ba(ClO2)2 + H2SO4 → BaSO4 + 2HClO2

+1 : HXO : Hypohalous acid

X₂ + H₂O -> H⁺ +X⁻ + HOX

Strength of acid : HOCl > HOBr > HOI

| Oxidation state of Cl | Oxoacids  | Name  | Oxyanions | Name  | Sodium salts
| +1 | HOCl  | Hypochlorous acid  | ClO⁻ | Hypochlorite Ion | NaClO
| +3 | HOClO | Chlorous acid | ClO₂⁻ | Chlorite ion  | NaClO₂
| +5 | HOClO₂ | Chloric acid  | ClO₃⁻ | Chlorate ion  | NaClO₃
| +7 | HOClO₃ | Perchloric acid  | ClO₄⁻ | Perchlorate ion | NaClO₄

Hypochlorite ion (+1) and its salt

1.     Electrolysis of cold brine

Then the chlorine gas is allowed to mix with hydroxide ion

2.     Reaction of CaO and Ca(OH)₂ , CaCl₂ and Ca(ClO)₂ are known as bleaching agent

Halide ion(+3) and its salt

Only NaClO₂ and used as bleaching agent

2 ClO₂ + 2 NaOH +H₂O₂ ->2NaClO₂ + 2H₂O + O₂

Halate ion (+5) and its salts

Electrolysis of hot brine

3X2 + 6OH− → XO3- + 5X− + 3H2O

# data[].attributes.body
Know as the halogen because

-  Can be found as salts of the halide ion because of their high reactivity;

- Have 7 electron  and form singly bonded diatomic molecules, X2-

Physicochemical Properties of elements
( Increase down the group )

-  Melting and boiling point, colour intensity, atomic and ionic radius and density

( Decrease down the group )

-  Ionization energy, electronegativity and oxidizing power

Industrial preparation of the elements

Fluorine

- Electrolysis of HF dissolved in molten KF ( obtained at the anode )

Chlorine

- By electrolysis of molten NaCl in Down Cell and brine in Keller – Solvay method or Chlor – alkali cell

Bromine

-Extracted by passing chlorine gas into conc. sea water

Laboratory preparation of the elements

-Reacting of solution of halide ions with any substance that is stronger oxidizing agent

-  Reaction of metal halide with strong oxidizing agent

- Chlorine – made by oxidation of conc HCl with KMnO4.

Chemical Properties

- Halogen as oxidizing agent but decrease down the group ( because of high electronegativity )

-  React with H2S and undergo redox reactions

-  Reacts with water and disproportionation reaction occur (expect for fluorine )

- React with non-metal and forms covalent compound

- React with metal (s-block -> ionic), ( d and p block -> ionic) (p-block -> show some covalent characters)

Test to identify halide ions

1.      Add conc. h2SO4 and heat

2.      Add AgNO3 followed by NH3

3.      Add cl2 or acidic NaClO and then CCl4

Compound of the Halogen
- Hydrogen Halides , HF ( can be industrially prepared by the reaction of fluorspar with sulphuric acid )

-  HX ( X = Cl, Br, I ) industrially prepared by direct reaction of hydrogen and halogen

-  Laboratory prepared by using reaction of phosphoric acid with halide salts in presence of P2O5.

Physical properties of the hydrogen halides, HX

-Thermal stability : HF > HCl > HBr > Hl

-Acid strength : HF<< HCl <HBr < Hl

Chemical properties of hydrogen halides, HX

- Reacts with metal oxides, hydroxides and carbonates

-  Reacts with metals above hydrogen in the Electrochemical Series.

- Act as a reducing agents

Oxoacid of halogen

-  Cl, Br and I forms of 4 types of oxoacid
>> (+7) Perhalic acid
>> (+5) Halic acid
>> (+3) Halous acid
>> ( +1) Hypohalous acid

-   Fluorine only can form one oxoacid ( Hypofluorous acid )

- Increase of numbers of O will increase the acidity. ( eg : HOCl < HOClO < HOClO2 < HOClO3 )

1.      Hypochlorite ion , ( +1)

-  Electrolysis of cold brine (chlor-alkali industry)

-  Produce will produce at the anode

2.      Halite ions,  (+3)

-  Salts used as bleaching and oxidizing agent. The salts also produced by reaction of ClO2 with NaOH and H2O2

3.      Halate ion ( +5)

- Electrolysis by hot brine

# data[].attributes.body
Group VllA elements are known as Halogen
- found as salts of the halide ion because of their high reactivity.
-seven valence electrons , need only one electron to achieve an octet

Down Group - increases in:

- melting point & boiling point
- colour intensity
- atomic & radius
- density of the elements.

Down Group - decreases in:

- Ionization energy
- Electronegativity
( Fluorine: highest electronegativity: needs 1 electron to fulfill octet,  easily remove an electron from a nearby atom.
- oxidizing power

Chemical Properties

- halogen as a good oxidizing agent
(high electronegativity of halogen)
a) Displacement reaction
b) Reaction with H₂S
c) Reactions with water (disproportionate reaction except fluorine)
d) Reactions with alkali solution (form halide ion + hypohalite + water) (disproportionate reaction except fluorine)
e) Reactions with non-metallic elements (form covalent bond)
f) Reactions with metals

Compounds of Halogen

1. Hydrogen Halides(HX) : HF,HCl,HBr,HI

- Thermal Stability : HF > HCl > HBr > HI
- Acid Strength : HF < HCl < HBr < HI
HF is weak acid: high electronegativity differences,  need more energy to break the bond, H+ ions more hard to lost

- Reacts with metals above hydrogen in Electrochemical Series
- Reacts with metal oxides, hydrogens, and carbonates
- HF react with glass
- HX as reducing agent
strength : HCl < HBr < HI

2. Oxoacids of Halogen
- HXO (Hypohalous acid) +1
- HOXO (Halous acid) +3
- HOXO2 (Halic acid) +5
- HOXO3 (Perhalic acid) +7

- The acid strength
: HOX < HOXO < HOXO2 < HOXO3
- number of lone oxygen increase, acidity increase
- oxoacid becomes a better proton donor (stronger acid)

3. Oxyanion and salts

- HClO ( Hypochlorous acid )+1
- HOClO (Chlorous acid) +3
- HOClO2 (Chloric acid) +5
-  HOClO3  (Perchloric acid) +7

# data[].attributes.body
-Halogen found as salt of halide ion because of their reactivity
- INCREASE down the group :
1. melting and boiling point
2. Colour intensity
3. Atomic radius and ionic radius
4. Density of elements
-DECREASE down the group :
1. Ionization energy
2. electronegativity
3. oxidizing power

Industrial preparation
FLOURINE - electrolysis of HF dissolved in molten KF
CHLORINE - Electrolysis of molten NaCl in Down cell and Chlor-alkali cell
BROMINE - Extracted by passing chlorine gas into conc. sea water.

Laboratory preparation
1. Reaction a solution of the halide ions with any substances that stronger oxidizing agent
2.Reaction of metal halide , with strong oxidizing agent
3. Oxidation of conc HCl with MnO2 and KMnO4.
4. Solution of Cl2 in water by reacting bleaching powder with HCl.

COMPOUND OF HALOGEN
1.Hydrogen Halides (HX)
2.Oxoacid of Halogen
3.Oxyanion and salts of halogen

Acid strength of HX
HF<<HCl<HBr<HI

Strength as reducing agent
HCl<HBr<HI

# data[].attributes.headline
Nur Syafiqah binti Kamaruddin (A21SC0260)

# data[].attributes.subject
Nur Syafiqah binti Kamaruddin (A21SC0260)

# data[].attributes.body
Group VIIA : Halogen
- found as salts of halide ion because their high reactivity.
- has 7 valence electrons, only one e- to achieve noble gas configuration.
- they form singly bond d diatomic, X2.

Going down the group
Increase in ;
- melting & boiling point
- color intensity
- atomic & ionic radius
- density of the elements (F<Cl<Br<I<At)

Decrease in;
- ionization energy
- electronegativity
- oxidizing power

Industrial Preparation
Fluorine
• obtained by an electrolysis of HF dissolved in molten KF.
• KF in the mixture serves as an electrolyte
Chlorine
• electrolysis of molten NaCl in Downs Cell.
• electrolysis of brine in Kellner-Solvay method or using Clor-alkali cell.
Bromine
• extracted by passing chlorine gas into concentrated sea water.

Laboratory Preparation
1. Reacting a solution of the halide ions with substance that is stronger oxidizing agent.
2. Reaction of metal halides, MX, with strong oxidizing agent such as MnO₂ presence of acid.
3. Chlorine can be made by oxidation of concentrated HCl with MnO₂ or KMnO₄
4. Solution of Cl₂ in water is readily obtained by reacting bleaching powder, CaCl₂•Ca(ClO)₂

Application
Fluorine
- used as fluorinating agent for organic compounds.
Chlorine
- used in the manufacturing of organic and inorganic chemicals
- in water treatment
Bromine
- fuel additives
- plants protection agents

Chemical Properties
halogen as good oxidizing agent(high electronegativity of halogen)
a) Displacement reaction
b) Reaction with H₂S
c) Reactions with water
d) Reactions with alkali solution (form halide ion + hypohalite + water)
e) Reactions with non-metallic elements (form covalent bond)
f) Reactions with metals

Compounds of Halogen
1. Hydrogen Halides(HX)
Industrial
- manufactured industrially by reaction of CaF₂, with H₂SO₄
- direct reaction of hydrogen and halogen except F

Laboratory
- Reaction of halide salt(NaCl with concentrated sulfuric acid)
- not suitable for HBr and HI, the hydrides will be oxidized by the acid.
-reactions of H₃PO₄ with halide salt in presence of P₂O₅ (more suitable)

Physical Properties
- Thermal Stability : HF > HCl > HBr > HI
- Acid Strength : HF << HCl < HCl < HI
HF is weak acid because high electronegativity differences, does not let hydrogen go easily, need more energy to break the bond

Chemical Properties
- Reacts with metals above hydrogen in Electrochemical Series
- Reacts with metal oxides, hydrogens, and carbonates
- HX as reducing agent

2. Oxoacids of Halogen
HOX, Hypohalous acid (+1)
-prepared by hydrolysis of halogen (disproportionation)
-weak acid
-oxidizing agents

Halous acid, HOXO (+3)
-HOCIO more stable than HOBrO and HOIO
-prepared by chlorine dioxide + H₂S₂ + barium hydroxide

Halic acid, HOXO2 (+5)
-only HOIO₂ can be prepared easily by reaction of iodine with nitric acid.

Perhalic acid, HOXO3 (+7)
- HOClO3 can be prepared by catalytic oxidation
- strong acid and powerful oxidizing agent

Effects of Numbers of Oxygen on the Acidity
- number of lone oxygen attached to central atom affects the acidity of oxoacids.
- more lone oxygen, better proton donor

3. Oxyanion and salts of halogen
i) XO : (hypo -ite ion)
prepared by electrolysis of cold brine & reaction of CaO of Ca(OH)₂ with chlorine

ii) XO₂ +1 : (-ite ion)
prepared by reaction of ClO₂ with NaOH and H₂O₂

iii) XO₃ +5 : (-ate ion)
prepared by electrolysis of hot brine & oxidation of halide ion (-1) by hypochlorite ion (+1)

iv) XO₄ +7 : (-per ate ion)
mainly utilized fireworks

Oxides of Halogen
Cl₂O₆
• highly unstable red molecules
• preparation : anhydride chloric + perchloric acid, ClO₂+ & ClO₄-

Cl₂O₇
• dehydrating concentrated perchloric acid with P2O5 and distilling (-35C, 1 mm Hg pressure)

I₂O₅
• white solid
• decompose at temperature > 300°C
• preparation : dehydrating ionic acid at 200°C in a steam of dry air

# data[].attributes.body
Group VIIA (Halogen)

- Found as salts of the halide ion because of their high reactivity.
- Each atom has 7 valence and therefore need only one electron to achieve a noble gas configuration

Down the group :

- Regular increase in melting point & boiling point, colour intensity, atomic radius & ionic radius, density of the elements
- Regular decrease in ionization energy, electronegativity, oxidizing power

Industrial Preparation

a) Fluorine

- Obtained by an electrolysis of HF dissolved in molten KF

b) Chlorine

Electrolysis of molten NaCl in Downs Cell

Electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell

c) Bromine

Extracted by passing chlorine gas into concentrated sea water

Laboratory Preparation

1. Reacting a solution of the halide ions with any substance that is stronger oxidizing agent

2. Reaction of metal halide with strong

oxidizing agent (in presence of acid)
3. Chlorine can be made by oxidation of

concentrated HCI with Mn04 or KMn04
4. Solution CI2 in water obtained by reacting CaCI2.Ca(CIO)2 or NaOCI with HCI

Application of Elemental halogen

a) Fluorine
- Mainly used as fluorinating agent for organic compounds. Highly fluorinated organic derivatives are now widely used in polymers, refrigerant fluids, aerosol propellants and noninflammable anesthetics

b) Chlorine
- In the manufacture of organic and inorganic chemical, in paper and pulp industry (to bleach the pigment), in water treatment, in cleaning and sanitation

c) Bromine
- Mainly utilized in the manufacture of organic chemical
- Utilized in the manufacture of fuel additives, flame retardants, plants protection agents

Chemical properties

- Halogen as good oxidizing agent because of high of electronegativity of halogen

(a) Displacement reaction

(b) Reaction with H2S

(c) Reactions with water

(d) Reaction with alkali solution :  form halide ion + hypohalite + water

(e) Reactions with non-metallic elements
- Halogens form covalent bonds in compounds with non-metallic elements

(f) Reactions with metals

Industrial preparation

a) HF
- Manufactured industrially by the reaction of fluorspar

CaF2+ H2S04 at 200°C- 350°C.

b) HX (X = C1, Br, I)
- Manufactured industrially by direct reaction of hydrogen and halogen

Laboratory preparation of HX (X = Cl, Br, I)

- Reaction of halide salts e.g NaCl with concentrated sulfuric acid
- More suitable method for the preparation of HX the reaction of phosphoric acid a poor oxidizing agent) with halide salts in the presence of P2O5

PHYSICAL PROPERTIES

- Thermal stability of HX : HF> HCI> HBr> HI
- Acid strength of HX : HF< HCI< HBr< HI

Oxoacid of Halogen

- HXO (Hypohalous acid) +1
- HOXO (Halous acid) +3
- HOXO2 (Halic acid) +5
- HOXO3 (Perhalic acid) +7

- The acid strength of oxoacid is HOX < HOXO < HOXO2 < HOXO3

OXYANION

- ite(+1,+3)
- ate (+5.+7)
- hypo - lowest oxidation no
- per - highest oxidation no

Preparation

a) Hypochlorite ion (+1)
- Prepared by Electrolysis of cold (15 °C) brine (Chlor-alkali industry)
- Reaction of Cad or Ca(OH)2 with chlorine

b) Halite ion (+3)
- The salts are produced by reaction of CIO2 with NaOH and H202

c) Halate ion (+5)
- Prepared by Electrolysis of hot (70 °C) brine

Perhalate ion (+7)

NaCIO3 + H20 -> NaCIO4 + H2

Potassium and ammonium salt

produced by : NaCIO4 + MCI -> MCI04

+ NaCI (M= K,NH4*)

Oxides

a) C1206
- Red molecule
- Preparation : Anhydride chloric + perchloric acid, CI02* & CIO4

b) C1207
- Dehydrating concentrated perchloric acid with P205 and distilling (-35C 1 mm Hg pressure)

c) I205
- White solid
- Decompose at temperature > 300°C
- Preparation : Dehydrating ionic acid at 200°C
in a stream of dry air

I205+500 -> I2 + 5C02

# data[].attributes.body
GROUP VIIA: Halogen
-each atom has 7 valence electron
-found as salts of the halide ion due to high reactivity.
-ionization energy and electronegativity decrease down group.
-atomic radius, ionic radius and colour intensity increase down the group.

*industrial preparation
>fluorine
-obtained by electrolysis of HF in dissolve molten KF
>Chorine
-Electrolysis of molten NaCl in Down cell
-Electrolysis of brine in kellner-solvay method or using chlor-alkali cell
>bromine
-extracted by passing chlorine gas into concentrated sea water.

*Application
>fluorine
-used as fluorinating agent for organic compounds.
>chlorine
-in manufacture of organic and inorganic chemical.
>bromine
-utilized in the manufacture of additives, flame retardants, plants protection agents.

*laboratory preparation
-reaction of halide salts with concentrated sulfuric acid
-reaction of phosphoric acid with halide salts in the presence of P2O5

*physical properties
-thermal stability of HX : HF>HCl>HBr>HI
-acid strenght of HX : HF<HCl<HBr<HI

*Oxoacid of halogen
- Perhalic acid,HOXO3(+7)
- Halic acid,HOXO2(+5)
-Halous acid,HOXO(+3)
-Hypohalous acid,HXO(+1)

*preparation
(hypohalous acid,HOX)
-hydrolysis of halogen:disproportionation reaction
-HOX(X=Cl,Br,I) are weak acid

HOCl>HOBr>HOI
-Oxidizing agent

(Halous acid,HOXO)
-only HOClO is important(stable than HOBrO and HOIO)

(Halic acid,HOXO2)
-only HOIO2 easily be prepared and isolated from its aqueous solution.

(perhalic acid,HOXO3)
-prepared from the catalytic oxidation of the corresponding halate,XO3- followed by the addition of strong acid.

*oxides
>Cl2O6
-highly unstable red molecules
-mixture of anhydride of chloric and perchloric acid
>Cl2O7
-dehydrating concentrated perchloric acid with P2O5 and distilling(-35 degree celsius under 1mmHg pressure)
>I2O5
-white solid compound
-decompose at temperature >300 degree celsius
-dehydrating iodic acid at 200 degree celsius in a stream of dry air
-powerful oxidising agent.

# data[].attributes.body
Goup VIIA  halogen

Introduction
-The name "halogen" means "salt former", derived from the Greek words halo- ("salt") and -gen ("formation").
-The Group VIIA elements have seven valence electrons in their highest-energy orbitals (ns ² np ⁵).

Trends
-going down the group
-melting and boiling point increase
-atomic and ionic radius increase
-density increase
-first IE decrease
-elctronegativity decrease

Industrial Preparation
Flourine
-Electrolysis of HF
Chlorine
-Electrolysis of NaCl (Down Cell)
=Electrolysis of brine in Kellner-Solvay method or Chlor-alkali cell
Bromine
-Passing Cl₂ gas into concentrated sea water

Applications
Flourine
- Used as fluorinating agent for organic compounds.
Chlorine
- manufacture of organic and inorganic chemicals, paper and pulp industry, water treatment,cleaning and sanitation.
Bromine
-utilized in manufacture of organic chemicals

Chemical Properties
Displacement reaction
-ability of halogen as oxidizing agent decrease going down the group
React with H2S
-H2​S+X2​(Cl,Br,I=X)→2HX+S
React with water
-X2 + H20 → HOX/HX
React with alkali
React with metal

Hydrogen halide(HX)
Physical properties
Thermal stability:decrease going down the group
Acid strength: increase going down the group
Chemical properties
- react with metals above hydrogen in Electrochemical Series
- react with metal oxide, hydroxides, and carbonates
-HF reacts with glass
-HX is a reducing agent

Oxoacid
+1-hypohalous acid
+3-halous acid
+5-halic acid
+7-perhalic acid

# data[].attributes.headline
Nurul Amira Najwa Binti Mohamad Azman (A21SC0303)

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Nurul Amira Najwa Binti Mohamad Azman (A21SC0303)

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Group VIIA Halogen

-found as salts of the halide ion because of their high reactivity.
-each atom has 7 valence electron therefore need only one electron to achieve a noble gas configuration.

TREND (down the group)
INCREASE in melting point & boiling point, colour intensity , atomic radius & ionic radius , density of the elements.
DECREASE in ionization energy , electronegativity ,oxidizing power

INDUSTRIAL PREPARATION
Fluorine
-obtained by electrolysis of HF dissolved in molten KF
Chlorine
-electrolysis of molten NaCl in Downs Cell / electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell
Bromine
-extracted by passing chlorine gas into concentrated sea water
LABORATORY PREPARATION
1. Reacting a solution of the halide ions with any substance that is stronger oxidizing agent

2. Reaction of metal halide with strong oxidizing agent (in presence of acid)

3.Chlorine can be made by oxidation of concentrated HCl with MnO4 or KMnO4

4. Solution Cl2 in water obtaioned by reacting CaCl2.Ca(ClO)2 or NaOCl with HCl

APPLICATION
Fluorine - used as fluorinating agent for organic compounds
Chlorine - in manufacture of organic and inorganic chemicals, in paper and pulp industry, in water treatment, in cleaning and sanitation
Bromine - utilized in the manufacture of fuel additives, flame retardants, plants protection agents

CHEMICAL PROPERTIES

-Halogen as good oxidizing agent because of high of electronegativity of halogen
(a) Displacement reaction
(b) Reaction with H2S
(c)Reactions with water
(d)Reaction with alkali solution: form halide ion+ hypohalite + water
(e)Reactions with non-metallic elements:
(f)Reactions with metals

INDUSTRIAL PREPARATION
HF- manufactured industrially by the reaction of fluorspar CaF2+ H2SO4at 200– 350°C.
HX (X = Cl, Br, I)- manufactured industrially by direct reaction of hydrogen and halogen
LABORATORY PREPARATION
•Reaction of halide salts with concentrated sulfuric acid
•The reaction of phosphoric acid with halide salts in the presence of P2O5
PHYSICAL PROPERTIES
* Thermal stability of HX: HF> HCl> HBr> HI
* Acid strength of HX: HF< HCl< HBr< HI

Oxides
Cl2O6
Preparation: anhydride chloric + perchloric acid, ClO2+ & ClO4-

Cl2O7
Preparation : Dehydrating concentrated perchloric acid with P2O5 and distilling (-35C ,1 mm Hg pressure)

I2O5
Preparation: dehydrating ionic acid at 200C in a stream of dry air     I2O5+5CO —> I2 + 5CO2

Oxoacid of Halogen

HXO (Hypohalous acid) +1

HOXO (Halous acid) +3

HOXO2 (Halic acid) +5

HOXO3 (Perhalic acid) +7

-The acid strength of oxoacid of is
HOX < HOXO < HOXO2 < HOXO3

OXYANION

-ite (+1,+3)

-ate (+5,+7)

hypo- lowest oxidation no.

per- highest oxidation no.

PREPARATION
Hypochlorite ion (+1)
- Prepared by Electrolysis of cold (15 °C) brine (Chlor-alkali industry)
- Reaction of CaO or Ca(OH)2 with chlorine
Halite ion (+3)
-  The salts are produced by reaction of ClO2 with NaOH and H2O2
Halate ion (+5)
- Prepared by Electrolysis of hot (70 °C) brine.

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Introduction
-Element in group 7 found as salts of halide ion due to high reactivity.
-Decrease in IE, electronegativity, oxidizing power down the group.

Fluorine
-obtain by electrolysis of HF dissolve in molten KF

Chlorine
obtaine by:
1)electrolysis of molten NaCl in Down cell
2)electrolysis of brine Kellner-Solvay method or using Chlor-alkali cell.

Bromine
extracted by passing chlorine gas into concentrated sea water.

uses of halogen element
Fluorine-used as fluorinating agent for organic compounds.
Chlorine-to bleach the pigment in paper and pulp industry
Bromine-used as utilized in the manufacture or organic chemicals

Test to identify halogen ions
1)add conc. H2SO4 and heat
Cl ions: HCl gas release
Br ions:HBr,SO2, and Br2 liberated
I ions:SO2, H2S and I2 liberated

2)add AgNO3(aq),followed by NH3(aq)
Cl ions:white ppt. dissolve in NH3(aq)
Br ions: yellowish/white ppt. dissolve in NH3(aq)
I ions: yellow ppt. sparingly dissolve in conc.NH3(aq)

3)add Cl2(aq) or acidic NaClO(aq) and CCl4(l)
Cl ions: No reaction
Br ions:Br2 released,brown CCl4 layer formed
I ions:I2 released,pink CCl4 layer formed

compound of halogen : hydrogen halides
industry preparation
manufactured industrially by the reaction of fluorspar(acidspar),CaF2 with sulfuric acid.

laboratory preparation
reaction of halide salt with conc. sulfuric acid.
2NaX(s) + H2SO4(l) --> Na2SO4 + 2HX(g)
(X=Cl,Br,I)
*but this method not suitable for preparation of HBr and HI because some of the hydride will be oxidize by the acic.

Physical properties
HF<<HCl<HBr<HI
----------------->
increase acid strength

Oxoacid of halogen

HOX(+1)

HOXO(+3)

HOXO2(+5)

HOXO3(+7)

HOCl<HOClO<HOClO2<HOClO3
--------------------------------->
increase acid strength because
-increase number oxygen atom which has tendency to pull electron density away from any atom because of the high electronegativity
-the more oxygen atom attached to cental atom, the OH bond will become more polar and the hydrogen atom will release easily to become H+ ions
-Therefore, the acidity increase

Oxyacids and its sodium salts of chlorine
1)HOCl(hypochlorous acid,ClO-,NaClO)
preparation:
-electrolysis of cold brine
Cl2 + 2NaOH --> NaCl + NaOCl + H2O
-NaOCl(aq),sodium hypochlorite solution is called as bleaching solution.

2)HOClO(chlorous acid,ClO2-,NaClO2)
preparation:
-reaction of ClO2 with NaOH and H2O2
2ClO2 + 2NaOH + H2O2 --> 2NaClO2 + 2H2O + O2
-the salt are use as bleaching and oxidizing agent

3)HOClO2(chloric acid,ClO3-,NaClO3)
preparation:
-electrolysis of hot brine
3X2 + 6OH- -->XO3- + 3H2O 5X-
-used as bleaching agent for paper pulp
-NaClO3 as defoliant and herbicide
-KClO3 as primary oxidant in fire work

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Group VIIA: Halogen
- found as salts of the halide ion due to their reactivity
- each atom has 7 valence electrons
-atomic radius, ionic radius and colour intensity increase down the group
-ionization energy and electronegativity decrease down the group

Industrial preparation:
a) fluorine:
- obtained by electrolysis of HF in dissolve molten KF
b) chlorine
- Electrolysis of molten NaCl in Down cell
- Electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell
c) bromine
- Passing chlorine gas into concentrated sea water

Laboratory preparation:
1. solution of halide ions + stronger oxidizing agent
2. metal halide + stronger oxidizing agent
3. Cl - made by oxidation of concentrated HCl with MnO2 or KMnO₄
4. Solution Cl₂ in water by CaCl₂.Ca(ClO)₂ or NaOCl + HCl

Application halogen:
1) Fluorine
- Used as fluorinating agent for organic compounds.
2) Chlorine
- in manufacture of organic and inorganic chemicals, paper and pulp industry, water treatment, cleaning and sanitation
3) Bromine
- mainly utilized in manufacture of organic chemicals

Chemical properties of Halogen:
-oxidizing agent (ability decrease from F2, Cl2, Br2 to I2 )
-react with H2S
-react with water ( disproportionation except F2)
-react with alkali solution
-react with non-metallic element (form covalent bonds)
-reaction with metals

Tests to identify halide ions
1) Add conc. H2SO4 and heat
-Cl →HCl gas released
-Br →HBr, SO2 & Br2 liberated
-I→SO2, H2S and I2 liberated

2) Add AgNO3 followed by NH3
-Cl →white ppt dissolve
-Br → yellowish-white ppt dissolve
-I → yellow ppt, sparingly

3)Add Cl2 or acidic NaClO and then CCl4
-Cl →no reaction
-Br → Br2 released, brown CCl4 layer formed
-I→I2 released, pink CCl4 layer formed

Compound of Halogen
1.Hydrogen Halides(HX)
Industrial preparation
HF - CaF2 + H2SO4
HX (Cl,Br,I) direct reaction of hydrogen and halogen

Laboratory preparation
-Reaction of halide salt with conc. H2SO4
*not suitable for preparation HBr and Hl, some hydride will oxidize by acid
-more suitable method
H3PO4 (poor oxidizing agent) + halide salts in the presence of P2O5

Physical properties of HX
a)Thermal stability:
HF>HCl>HBr>HI
b)Acid strength:
HF<<HCl< HBr < HI

Chemical properties
a)react with metals above hydrogen in Electrochemical Series
b)react with metal oxide, hydroxides and carbonates
c)HF react with glass
d)HX is reducing agent (HCl< HBr<HI)

2) Oxoacid of Halogen
HXO (hypohalous acid, +1)
- HOCl>HOBr>HOI (acid strength)
HOXO (halous acid, +3)
- HOClO more stable than HOBrO and HOIO
HOXO2 (halic acid, +5)
- only HOIO2 can be easily prepared ( iodine + nitric acid)
HOXO3 (perhalic acid, +7)
- strong acid and strong oxidising agent

Effect of  the number of oxygen on acidity of oxoacids
- number of lone oxygen increase, oxoacid become better proton donar (stronger acid)
HOCl< HOClO<HOClO2<HOClO3

3) oxyanion and salts of halogen
ClO- (hypochlorite ion, +1)
ClO2- (chlorite ion, +3)
ClO3- ( chlorate ion, +5)
- prepared by electrolysis of hot brine
ClO4- (perchlorate ion, +7)

4) Oxides of halogen
* Cl2O6
- highly unstable red molecules
- mixture of anhydride of chloric and perchloric acid
* Cl2O7
- dehydrating concentrated perchloric acid with P2O5 and distilling ( -35 degree celsius under 1mmHg pressure)
* I2O5
- white solid compound
- decompose at temperature > 300 degree celsius
- dehydrating iodic acid at 200 degree celsius in a stream of dry air
- powerful oxidising agent

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GROUP VIIA : HALOGEN
-each atom has 7 valence electron therefore need only 1 electron to achieve noble gas configuration
-form singly bonded diatomic molecules,x2
Down the group:-
1.increase melting point &boiling point
2.increase atomic radius & ionic radius
3.increase density
4.decrease ionization energy
5.decrease electronegativity (F  highest electronegativity)
6.decrease oxidizing power
Chemical properties:-
-as oxidizing agent because of high electronegativity compare to other elements
-ability as oxidizing agent decreases down the group
Reactions with:-
water

-only I2 & Cl2 can oxidize water
-serve as oxidizing & reducing agent
alkali solution
-form covalent bonds with non-metallic elements
-aqueous solution of non-metal halides undergo hydrolysis reactions
Industrial preparation:
Fluorine
-obtained by an electrolysis of HF dissolved in molten KF
Chlorine
-electrolysis of molten NaCl in Down Cell
-Chlor-alkali cell
Bromine
-extracted by passing chlorine gas into concentrared sea water

Halogen Compounds:-
Physical properties

Hydrogen halides

-thermal stability of HX:HF>HCl>HBr>HI
-acid strenght of HX:HF<HCl<HBr<HI
Chemical properties
-reacts with metal above hydrogen in the Electrochemical Series
- reacts with metal oxides, hydroxides and carbonates
- HF reacts with glass
- HX as reducing agent
HCl < HBr <HI

Oxoacid of Halogen

- +7 HOXO₃ (Perhalic acid)
- +5 HOXO₂ (Halic acid)
- +3 HOXO (Halous acid
- +1 HXO (Hypohalous acid)

Preparation
Hypohalous acid, HOX
- Hydrolysis of halogen : disproportionation reaction
- HOX (X = Cl, Br, I) are weak acid
HOCL > HOBr > HOI
- oxidizing agents
Halous acid, HOXO
- only HOClO is important (stable than HOBrO and HOIO)
- Ba(OH)₂ + H₂O₂ + 2ClO₂ -> Ba(ClO₂)₂ + 2H₂O + O2
- Ba(ClO₂)₂ + H₂SO₄ -> BaSO₄ + 2HOClO2
Alic acid, HOXO ₂

-only HOIO2 easily be prepared and isolated from its aqueous solution.
- I₂ + 10HNO₃ -> 2HOIO₂ + 10NO₂ + 4H₂O

Perhalic acid, HOXO ₃
- Prepared from the catalytic oxidation of the corresponding halate,XO₃⁻ followed by the addition of a strong acid.

Oxyanion and salts of halogen

- +1 XO (hypo - ite ion)

- +3 XO₂ ( - ite ion)

- +5 XO₃ ( - ate ion)

- 7 XO₄ (per - ate ion)

Oxides
Cl₂O₆

Red molecule

Preparation - mixture of anhydride chloric and perchloric acid

Cl₂O₇

Dehydrating concentrated perchloric acid with P₂O₅ and distilling product at -35oC, 1mm Hg pressure

I₂O₅

White solid

Decompose at temperature higher than 300oC

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HARRIS NAQIUDDIN BIN ZAKARIA (A21SC0088)

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HARRIS NAQIUDDIN BIN ZAKARIA (A21SC0088)

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SUMMARY OF GROUP VIIA HALOGEN

-found as salts of the halide ion

-Each atom has 7 valence Electrons

-form singly bonded diatomic molecules

TREND OF HALOGEN DOWN THE GROUP

-Regular increase in boiling point,melting point,colour intensity,atomic radius,ionic radius and density of the elements

-Regular decrease in ionization energy,electronegativity and oxidizing power

INDUSTRIAL PREPARATION

1.FLUORINE

-Electrolysis of HF dissolve in molten KF

2.CHLORINE

-Electrolysis of molten NaCI in downs cell

-Electrolysis of brine in high concentration of NaCI solution in water method or using Chor-alkali cell

-Kellner-Solvay method

3.BROMINE

-Extracted by passing Chlorine gas into concentrated sea water

LABORATORY PREPARATION

-Reacting a solution of the halide ions with any substance that is stronger oxidizing agent

-Reaction of metal halide with strong oxidizing agent

-Oxidation of concentrated HCI with MnO2 or KMnO4 (chlorine)

-readily obtained by reacting bleaching powder, CaCl2 . (ClO2) or bleaching solution,

NaOCl with HCl (chlorine)

APPLICATION OF ELEMENTAL HALOGEN

1.FLUORINE

-used as fluorinating agent for organic compounds

2.CHLORINE

-In the manufacture of organic and inorganic chemicals

-In paper and pulp industry (to bleach the pigment)

-In water treatment

-In cleaning and sanitation

3.BROMINE

-Mainly utilized in the manufacture of organic chemicals

CHEMICAL PROPERTIES

-serves as oxidizing agents due to high electronegativity

-the ability of halogen as oxidizing agent decreases going down the group

REACTION WITH WATER

-With the exception of fluorine, the halogen reacts with water in a disproportionation reaction

-specific type of redox reaction in which an element from a reaction undergoes both oxidation and reduction to form two different products

REACTION WITH H2S

REACTION WITH ALKALI SOLUTION

-The hypohalite, XO- tends to disproportionate further

REACTION WITH NON-METALLIC ELEMENTS

-Halogens form covalent bonds in compounds with non-metallic elements

REACTION WITH METALS

-Halides of d block and p block metals in low oxidation state are ionic

-Halides of d block and p block metals in high oxidation state show some covalent character

-MX 2 (M = Be and Mg ; X = Cl , Br, I) have some covalent character

-Halides of s block metals are ionic

HALOGEN COMPOUNDS

1. HYDROGEN HALIDES

Industrial Preparation (HF): manufactured industrially by the reaction of fluorspar(acidspar ), CaF 2 , with H2SO4 at 200 350 °C.

Industrial Preparation (HI,HCI,HBr): are manufactured industrially by direct reaction of hydrogen and halogen

Application of HF: In the manufacture of aluminum fluoride, boron trifluoride ,uranium tetrafluoride and ammonium hydrogen fluoride

Application of HCI: Neutralization in inorganic and organic chemistry

Laboratory Preparation: Reaction of Halide salts with concentrated sulfuric acid

Physical Properties:

-HF>HCI>HBr>HI (Thermal stability)

-HF<HCI<HBr<HI (Acid strength)

Chemical properties:

-Reacts with metals above hydrogen in the Electrochemical Series

-Reacts with metal oxides, hydroxides and carbonates

-HF reacts with glass

-HX as reducing agent

2. OXOACID OF HALOGEN

-Perhalic acid,HOXO3 (+7)

-Halic acid,HOXO2 (+5)

-Halous acid,HOXO (+3)

-Hypohalous acid,HXO (+1)

PREPARATION

a) Hypohalous acid,HXO

- Hydrolysis of halogen: disproportionation reaction Chlorine, bromine and iodine are slightly soluble in water

(b) Halous acid, HOXO

- Chlorous acid is prepared by reaction of chlorine dioxide

with hydrogen peroxide in the presence of barium hydroxide. The barium chlorite precipitated is then reacted with sulfuric acid to release chlorous acid

c) Halic acid, HOXO2

- from its aqueous solution. It is prepared by reaction of iodine with Nitric acid

d) Perhalic acid, HOXO3

- catalytic oxidation of the corresponding halite, XO3- followed by the addition of a strong acid

3. OXYANION AND SALTS OF HALOGEN

-Hypo-ite ion,XO- (+1)

-ite ion,XO2- (+3)

-ate ion,XO3- (+5)

-Per-ate ion,XO4- (+7)

OXIDES OF HALOGEN

- Most of the oxides of halogen are unstable

1. Dichlorine hexoxide, Cl2O6 is highly unstable red molecule. In solid phase,

it is a mixture of anhydride of chloric and perchloric acid, ClO2+ ClO4-

2. Dichlorine heptoxide, Cl2O7 may be prepared by carefully dehydrating concentrated perchloric acid with P 2 O 5 and distilling the product at 35 °C under 1mm Hg pressure.

3. Diiodine pentoxide, I2O5 , is a white solid compound and decomposes only at temperature higher than 300 °C. It is prepared by dehydrating iodic acid at 200 °C in a stream of dry air.

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Group VIIA Halogen

-found as salts of the halide ion
-each atom has 7 valence electron

TREND (down the group)
INCREASE
• melting point & boiling point
• colour intensity

• atomic radius & ionic radius
• density of the elements.
DECREASE
• ionization energy
• electronegativity
• oxidizing power

INDUSTRIAL PREPARATION
Fluorine
-electrolysis of HF dissolved in molten KF
Chlorine
-electrolysis of molten NaCl in Downs Cell / electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell
Bromine
-extracted by passing chlorine gas into concentrated sea water
LABORATORY PREPARATION
1) Solution of halide ions with any substance that is stronger oxidizing power
2) Metal halide with strong oxidizing agent
3) Cl can be made by oxidation of conc. HCl with MnO 2 or KMnO ⁴
4) Solution Cl ² in water is readily obtained by reacting CaCl ².Ca(ClO)² or NaOCl with HCl

APPLICATION
Fluorine → mainly used as fluorinating agent for organic compounds
Chlorine → in the manufacture of organic and inorganic chemicals, in paper and pulp industry, in water treatment, in cleaning and sanitation
Bromine → mainly utilized in the manufacture of fuel additives, flame retardants, plants protection agents

CHEMICAL PROPERTIES
-Halogen as good oxidizing agent because of high of electronegativity of halogen
(a) Displacement reaction
From the values of E0 SRP, electron affinity, and electronegativity, the ability of halogen as oxidizing agent decrease down the group. ( F2 > Cl2 > Br2 > I2 )
(b) Reaction with H2S
X2(aq) + H2S → 2HX(aq) + S(s) (X=Cl, Br, I)

TEST OF HALIDE IONS
-  add conc.H2SO4 and heat
-  add AgNO3(aq), followed by NH3(aq)
-  add Cl2(aq) or acidic NaClO(aq) and then CCl4(l)
HYDROGEN HALIDES
INDUSTRIAL PREPARATION
HF- manufactured industrially by the reaction of fluorspar CaF2+ H2SO4at 200– 350°C.
HX (X = Cl, Br, I)- manufactured industrially by direct reaction of hydrogen and halogen
LABORATORY PREPARATION
•Reaction of halide salts with concentrated sulfuric acid
•The reaction of phosphoric acid with halide salts in the presence of P2O5
PHYSICAL PROPERTIES
🌸Thermal stability of HX: HF> HCl> HBr> HI
🌸Acid strength of HX: HF< HCl< HBr< HI

Oxoacid of Halogen

HXO (Hypohalous acid) +1

HOXO (Halous acid) +3

HOXO2 (Halic acid) +5

HOXO3 (Perhalic acid) +7

-The acid strength of oxoacid of is
HOX < HOXO < HOXO2 < HOXO3

OXYANION

-ite (+1,+3)

-ate (+5,+7)

hypo- lowest oxidation no.

per- highest oxidation no.

PREPARATION
Hypochlorite ion (+1)
•Electrolysis of cold (15 °C) brine (Chlor-alkali industry)
•Reaction of CaO or Ca(OH)2 with chlorine
Halite ion (+3)
• The salts are produced by reaction of ClO2 with NaOH and H2O2
Halate ion (+5)
• Electrolysis of hot (70 °C) brine.

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Halogen :
- found as salts of the halide ion because of their hight reactivity.
- each atom has 7 valence electrons
- need only one electron to achieve a noble gas configuration.
- atomic radius and ionic radius increases down the group
- colour intensity increases down the group
- ionization energy decreases down the group
- electronegativity decreases down the group.

Fluorine
- has the highest electronegativity of all the elements
- due to hight electronegativity it can easily remove an electron from a nearby atom
- obtained by an electrolysis of HF dissolved in molten KF
- mainly used as fluorinating agent for organic compounds

Chlorine
- obtained by electrolysis of molten NaCl in Downs cell
- obtained by electrolysis of brine in Kellner-Solvay method or Chlor-alkali cell
- in water treatment and in cleaning and sanitation

Bromine
- extracted by passing chlorine gas into concentrated sea water. The bromide ion is oxidized to molecular bromine. Then, air is passed through the seawater to vapourize bromine and transfer the gas into sulfite solution. The sulfite will reduce bromine to bromide ion. Finally, chlorine gas is used to oxidize the bromide ion back to molecular bromine before distilling the pure bromine out.
- mainly utilized in the manufacture of organic chemicals

- because of high electronegativity of halogen compared to other elements, they tend to gain electrons from other substances and thereby serves as oxidizing agents.

Reaction of water
- with the exception of fluorine, the halogen reacts with water in a disproportionation reaction. Specific type of redox reaction in which an element from a reaction undergoes both oxidation and reduction to form two different products.

Reactions with non-metallic elements
- aqueous solution of non metal halides undergo hydrolysis reactions

* Halides of s block metals are ionic, halides of d block and p block metals in low oxidation state are ionic, halides of d block and p block metals in high oxidation state show some covalent character

Compounds of halogen
1. Hydrogen halides
- HF is manufactured industrially by the reaction of fluorspar with sulphuric acid
- used in the manufacture of aluminium fluoride, boron trifluoride, uranium tetrafluoride and ammonium hydrogen fluoride
- HCL, HBR, HI prepared by reaction of phosphoric acid with halide salts in the presence of P2O5.
- physical properties of hydrogen halide
acid strength of HX : HF<HCL<HBR<HI
- chemical properties of hydrogen halide
reacts with metal above hydrogen in the electrochemical series
reacts with metal oxides, hydroxides and carbonates

2. Oxoacid of halogen
i. hypohalous acid, HOX
- hydrolysis of halogen : disproportionation reaction.
-chlorine, bromine and iodine are slightly insoluble in water.
ii. halous acid , HOXO
- only chlorous acid is important because it is more stable than bromous acid and iodous acid.
iii. halic acid, HOXO2
- only iodic acid can easily be prepared and isolated from its aqueous solution.
- prepared by reaction of iodine with nitric acid.
iv. perhalic acid,HOXO3
- perchloric acid and periodic acid can be prepared from the catalytic oxidation of the corresponding halate followed by the addition of a strong acid.

3. Oxyanion and salts of halogen
the names of the oxyanions of the halogens use the ending -ite (+1, +3) and -ate (+5, +7) to indicate low and high oxidation numbers and the prefixes hypo- and per- to indicate the very lowest and very highest oxidation numbers.
4. Oxides of halogen
- most of the oxides of halogen are unstable
- Cl2O6 is highly unstable red molecule. In solid phase, it is a mixture of anhydride of chloric and perchloric acid
- Cl2O7 may be prepared by carefully dehydrating concentrated perchloric acid with P2O5 and distilling the product at -35°C under 1mm Hg pressure
- I2O5 is a white solid compound and decompose only at temperature higher than 300°C . It is prepared by dehydrating ionic acid at 200°C in a stream of dry air. As a powerful oxidizing agent, it will quantitatively convert CO into CO2

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Group IIVA Halogen

- found as salts of the halide ion because of their high reactivity
- each atom has 7 valence electron
- form singly bonded diatomic molecules

When going down the group,
*Regular increase in
- melting point and boiling point
- atomic radius and ionic radius
- density of the elements
*Regular decrease in
- ionization energy
- electronegativity
- oxidizing power

Industrial Preparation
- Fluorine ( an electrolysis of HF dissolved in molten KF )
- Chlorine ( Electrolysis of molten NaCl in Downs Cell , Electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell )
- Bromine ( extracted by passing chlorine gas into concentrated sea water )

Laboratory Preparation
1. Reacting a solution of the halide ions with substance that is a stronger oxidizing agent
2. Reaction of metal halide with strong oxidizing agent such as MnO2 in the presence of acid
3. Chlorine can also be made by oxidation of concentrated HCl with MnO2 or KMnO4
4. A solution of Cl2 in water is readily obtained by reacting bleaching powder or bleaching solution

Application
- Fluorine used as fluorinating agent for organic compounds
- Chlorine in the manufacture of organic and inorganic chemical, in paper and pulp industry, water treatment, cleaning and sanitation
- Bromine mainly utilized in the manufacture of organic chemicals such as fuel additives

Chemical Properties
- act as oxidizing agent ( high electronegativity, gain e )
- React with water in a disproportionation reaction
- Reaction with not-metallic elements ( form covalent bond in compounds )
- Reaction with metals ( form ionic compound )

Compounds of Halogen
1. Hydrogen halides
Industrial preparation
HF - reaction of CaF2 with H2SO4
HX (X= Cl, Br, I) - direct reaction of hydrogen and halogen

Laboratory preparation
- Reaction of halide salts with conc. H2SO4 ( not suitable for preparation of HBr and HI because some of the hydride will be oxidize by the acid )
- reaction of phosphoric acid with halides salts in the presence of P2O5

Physical Properties
- Thermal stabiliy og HX ;
HF > HCl > HBr > HI
- Acid strength
HF << HCl < HBr < HI

Chemical Properties
- react with metals above hydrogen in Electrochemical Series
- react with metal oxides, hydroxides, and carbonates
- HF reacts with glass
- HX as reducing agent

2. Oxoacid of Halogen
- Hypohalous acid ( oxi no = +1 )
* hydrolysis of halogen : disproportionation reaction
* weak acid , weaker than ethanoic acid
* oxidizing agent
- Halous acid ( oxi no = +3 )
* only chlorous acid, HOClO important because stable than bromous acid, HOBrO and iodous acid, HOIO
* HOClO prepared by reaction of chlorine dioxide with hydrogen peroxide in the presence of barium hydroxide
- Halic acid, HOXO2 ( oxi no = +5 )
* only iodic acid, HOIO2 can easily be prepared and isolated from its aqueous solution, prepared by reaction of iodine with nitric acid.
- Perhalic acid, HOXO3 ( oxi no = +7 )
* Can be prepared from the catalytic oxidation of the corresponding halate, XO3 - followed by the addition of a strong acid

- The effect of the number of oxygen on the acidity of oxoacids
* the more lone oxygen attached to the central atom, the more polar will be the O-H bond and the easier the hydrogen atom will be released as H+, thus increases the acidity of the acid.

3. Oxyanion and salts of halogen
- XO : hypo -ite ion
* prepared by electrolysis of cold brine and reaction of CaO or Ca(OH)2 with chlorine
- XO2 : -ite ion
* prepared by reaction of ClO2 with NaOH
- XO3 : -ate ion
* prepared by electrolysis of hot brine and oxidation of of halide ion (-1) by hypochlorite ion (+1)
- XO4 : per -ite ion
* used in fireworks

4. Oxides
- Dichlorine hexoxide, Cl2O6 highly unstable red molecule. Prepared by mixturing of anhydride chloric and perchloric acid
- Dichlorine heptoxide, Cl2O7 may be prepared by carefully dehydrating concentrated perchloric acid with P2O5 and distilling the product at -35 under 1mm Hg pressure
- Diiodine pentoxide, I2O5 is a white solid compound and decomposes only at temprature higher that 300. Prepared by dehydrating iodic acid at 200 in a steam of dry air

# data[].attributes.body
Group VIIA: Halogen

-From Greek word: "Hals": salt, "gennan" : generate ➡️generate salt from it
-has 7 valance e-
-found as salt of halide ion(high reactivity)
*eg: CaF, NaCl, Na₃AlF6

Physicochemical Properties:
-increase down a group
*atomic size
*affinity electron(except Cl< F)
*melting and boiling point (⬆️ in Van der Waals forces)
*density
*colour intensity
-decrease down a group
*ionization energy
*electronegativity
*oxidizing power
-physical appearance: gas to solid
-form singly in diatomic molecules (eg:F₂, Cl₂)

Industrial Preparation
-Fluorine
*electrolysis of HF dissolved in molten KF
-Chlorine
*electrolysis of molten NaCl in Downs Cell
*electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell
*Chlorine can be made by oxidation of conc. HCl with MnO₂ or KMnO₄
*A solution of Cl2 in water is readily obtained by reacting bleaching powder, CaCl₂.Ca(ClO)₂
-Bromine
*react a solution of the halide ions with any substance that is a stronger oxidizing agent
*reaction of metal halide, which MX with strong oxidizing agent such as MnO₂ in the presence of acid

Chemical Properties
-Halogen as oxidizing agent
*due to the high electronegativity of halogen
（a)Displacement reaction : the ability of halogen as oxidizing agent ⬇️going down the group; F₂>Cl₂>Br₂>I₂
#only the element at the upper can oxidize the element at lower when going down a group in the periodic table
(eg: F₂ can oxidize Cl-,Br- and I- ions)

(b) Reaction with H ₂ S: form hydrogen halide and Sulphur in solid form

(c)Reactions with water:
+the halogen reacts with water in a  disproportion reaction (except F)
+redox reaction: one element that undergoes oxidation and reduction to form 2 different products in a reaction

(d)Reaction with alkali solution: form halide ion+ hypohalite + water

(e)Reactions with non-metallic elements:
+halogens form covalent bonds in compounds with non-metallic
+aqueous solution of non-metallic halides will undergo hydrolysis reactions
(except CCl₄: due to C has no d orbital to receive a pair of e- from water molecule)

(f)Reactions with metals:
+most metals: F=catch fire, Cl, Br, I=combined when heated
+Au: reacts with F but not for Cl, Br, I
+Pt & Ag: does not react with Br, I
+Fe & Sn: react with F, Cl, Br, I

Compounds of Halogen
i) Hydrogen Halides, HX
*HF: reaction of CaF2 with H₂SO₄
*HX(Cl, Br, I): direct react of H2 and X₂
#Laboratory preparation:
~reaction of halide salts with conc. H₂SO₄ (cons: not suitable for HBr & HI due to some of the hydride will be oxidized by the acid)
~more suitable method: reaction of H₃PO4 with halide salts in the presence of P₂O₅
*Physical Properties:
#Thermal stability: decrease down a group
#Acid strength: increase down a group
*Chemical Properties:
#Reacts with the metals that above H in Electrochemical Series
#Reacts with MO,OH⁻,CO₃ ²⁻
#HF reacts with glass
#HX acts as reducing agent

ii)Oxoacid of Halogen
*Cl, Br, and I form 4 types of oxoacid:
#(+7) Perhalic acid
#(+5) Halic acid
#(+3) Halous acid
#(+1)  Hypohalous acid
*F only form one oxoxacid
#(HOF) Hypofluorous acid
*the effect of the numbers of O on the acidity of the oxoacids:
#the no. of lone oxygens⬆️, the oxoacid becomes a better proton donor, the stronger the acid

iii)Oxyanion and Salts of Halogen
*Names of Oxyanions for halogen:
#(+1, +3): -ite, prefix: hypo-
#(+5, +7): -ate, prefix: per-
*Hypochlorite ion (+1, ClO-) and its salts are IMPORTANT
#method of preparation:
+electrolysis of cold (15oC) brine (Chlor-alkali industry)
+reaction of CaO or Ca(OH)₂ with chlorine
*Halite ion(+3) and its salts
#only NaClO₂ is industrially important
#used as bleaching and oxidizing agent
#reaction of ClO₂ with NaOH and H₂O₂ produce salt, NaClO₂
*Halate ion (+5)and its salts
#preparation: electrolysis of hot (70oC) brine
#oxidation of halide ion by hypochlorite ion(+1)➡️applicable for preparation of iodate salt

# data[].attributes.body
Halogen
-In Greek word (Hals - salt)
(gennan - generate)
- founds as salts of halide ion
- F (Colourless) → Cl (Yellowish-green gas) → Br (Reddish - brown liquid) → I (Violet solid)
- has seven valance e⁻
- forn singly bonded diaotamic molecules, X2
- Regular increase in - Melting point, Boiling point, Colour intensity,  Atomic radius, Ionic, radius, Density of elements
- Regular decrease in - Ionization energy, Electronegativity, Oxidizing power

Industrial preparation
Fluorine
- obtained by electrolysis of HF in dissolved molten KF
Anode : 2F⁻ → F₂ + 2e⁻
Cathode : 2H⁺ + 2e⁻   → H₂
Chlorine
- Electrolysis of molten NaCl in Down cell
- Electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell
Bromine
- Passing chlorine gas into concentrated sea water

Laboratory preparation
- Reacting a solution of halide ions with any strong oxidizing agent
Bromine : 2Br⁻ + Cl₂ → Br 2 + 2Cl⁻
- Reaction of metal halide (MX) with strong oxidizing agent in the presence of acid.
(i)4MX + 4H₂SO₄ → 4MHSO₄ + 4HX
(i)4HX + MnO₂ → MnX2 + 2H₂O + X₂
(i)+(ii) 4MX + 4H₂SO₄ + MnO₂ → 4MHSO₄ + MnX₂ + + X₂ (X= Cl, Br,I)
- Oxidation of concentrated HCl with MnO2 or KMnO4 (Chlorine)
MnO2 + 2Cl− (aq) + 4H⁺ (aq) → Mn²⁺(aq) + Cl ₂ (g) + 2H₂O(l)
2MnO4 − (aq) + 16H⁺ (aq) + 10Cl⁻ (aq) → 2Mn²⁺(aq) + 5Cl ₂ + 4H₂O
- Reacting bleaching powder or solution (NaOCl) with HCl
Ca(ClO)₂ (s) + 4H⁺ (aq) + 2Cl− (aq) → Ca²⁺(aq) + 2H₂O(l) + 2Cl ₂ (aq)
2HCl(aq) + NaOCl(aq) → NaCl(aq) + H₂O(l) + Cl₂ (aq) - Chlorox

Chemical properties
- As oxidizing agent
- Reaction with H₂S
X₂ (aq) + H₂S → 2HX(aq) +S (s) ............X = Cl, Br, I
-Reaction with water
X ₂ (g) + H₂O(l) HOX(aq) + H+ (aq) + X− (aq) (X = Cl, Br, I)
0                              +1                           -1                    (undergo disproportionation reaction)
- Reaction with alkali solution
X ₂ (g) + 2OH− (aq) → X− (aq) + XO− (aq) + H₂O(l)
0                                   -1             +1                          (undergo disproportionation reaction)
- Reaction with non-metallic elements
Form covalent bonds in compound
- Reaction with metals except
Cl , Br , I does not react with Au
Br , I does not react eith Pt and Ag

Chemicals and ways to indentify halide ions
1.  Add cond. H2SO4 and heat
2. Add AgNO₃(aq) followed by NH₃ (aq)
3. Add Cl₂ (aq) or acidic NaClO(aq) and then CCl₄ (l)

Compunds of Halogen
1. Hydrogen Halides (HX)
Preparation
X= F.......CaF2 (s) + 2H₂SO₄ (aq,conc) → 2HF(g) + Ca(HSO₄ )₂ (aq )
H=Cl, Br, I .......H₂ (g) + X₂ (g) → 2HX(g)
.......2NaX(s) + H₂SO₄ (l) → Na₂SO₄ (aq) + 2HX(g)
.......3KX(s) + H₃PO₄ (aq) K₃PO₄ (aq) + 3HX(g) (most suitable)
Physical properties
Thermal stability :  HF > HCl > HBr > HI
Acid strength :  HF << HCl < HBr < HI
Chemical properties
- Reacts with metals above hydrogen in the Electrochemical Series.
- Reacts with metal oxides , hydroxides and carbonates.
- As reducing agent :  HCl < HBr < HI
- HF react with glass : 6HF + SiO₂ → H₂SiF₆ + 2H₂O

2.Oxacid of Halogen
-Hypohalous acid (HOX) (+1)
Preparation
Hydrolysis of halogen:  X₂ (g,l,s) + H₂O(l) H⁺ (aq) + X− (aq) + (aq)
-Halous acid (HOXO) (+3)
Only chlorous acid, HOClO is important
Preparation
(i)  Ba(OH)₂ + H₂O₂ + 2ClO₂ → Ba(ClO₂ )₂ + 2H₂O + O2
(ii) Ba(ClO₂ )₂ + H₂SO₄ → BaSO₄ + 2HClO 2
-Halic acid (HOXO ₂) (+5)
Only HOIO2  can easily be prepared
Preparation
I₂ (aq) + 10HNO₃ (aq) → 2HOIO ₂ (aq) + 10NO2 (g) + 4H₂O(l)
-Perhalic acid (HOXO ₃) (+7)
HOClO₃ and HOIO₃ can be prepared from the catalytic oxidation of the corresponding halate, XO3 − followed by the addition of strong acid
3. Oxyanion and salts of halogen
- Hypochlorite ion (+1)
Only hypochlorite ions (ClO– ) and its salts are important.
Preparation
(a)Electrolysis of cold (15 °C) brine (Chlor-alkali industry)
Anode : 2Cl− → Cl₂ (g) + 2e−
Cathode : 2H₂O + 2e⁻ → H2 + 2OH−
The chlorine gas produced at anode is allowed to mixed with hydroxide ion generated at cathode
Cl₂ + 2OH− → ClO− + Cl− + H₂O
or
Cl₂ + 2NaOH → NaCl + NaOCl + H₂O
(b) Reaction of CaO or Ca(OH)₂ with chlorine
2Cl₂ + 2CaO → CaCl₂ + Ca(OCl)2
2Cl₂ + Ca(OH)₂ → CaCl₂ + Ca(OCl)₂ + 2H₂O
-Halite ion (+3)
Only sodium chlorite, NaClO2 is industrially important.
Preparation
2ClO₂ + 2NaOH + H₂O₂ → 2NaClO ₂ + 2H₂O + O₂
-Halate ion (+5)
Preparation
Electrolysis of hot (70 OC) brine :  3X₂ + 6OH− → XO 3 - + 5X− + 3H₂O
X= Br,I ....... X- + 3ClO− → + 3Cl−
-Perhalate ions (+5)
Sodium, potassium, and perchlorates are particularly important industrially
Preparation
NaClO3 + H2O → NaClO4 + H2

4. Oxides of Halogen
- Oxidation state can be +1 until +7 according to different elements
Dichlorine hexoxide, Cl₂O₆ (+6) - highly unstable molecule
Dichlorine heptoxide, Cl₂O₇ (+7) -  may be prepared by carefully dehydrating concentrated perchloric acid with P₂O₅ and distilling the product at –35 °C under 1mm Hg pressure
Diiodine pentoxide, I₂O₅ (+5) - white solid compound and decomposes only at temperature higher than 300 °C.

# data[].attributes.headline
NURUL IDA KHAIRUNNISA BINTI MOHD USMAN (A21SC0314)

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NURUL IDA KHAIRUNNISA BINTI MOHD USMAN (A21SC0314)

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Group VIIA Halogen
- founds as salts of the halide ion ( high reactivity)
- has 7 valence electron
- they form singly bonded diatomic molecules

Trend down the group:
Regular increase in ;

melting point & boiling point

colour intensity

atomic radius & ionic radius

density of the elements

Regular decrease in ;

ionization energy

electronegativity

oxidizing power

Industrial Preparation
Fluorine
- electrolysis of HF dissolved in molten KF
Chlorine
- electrolysis of molten NaCl in Down Cell
- electrolysis of brine in Kellner-Solvay or Chlor-alkali cell
Bromine
- extracted by passing chloride gas into concentrated sea water.

Laboratory Preparation
1. Reacting a solution of the halide ions with any substance that is stronger oxidizing agent
2. Reaction of metal halide with strong oxidizing agent (in presence of acid)
3.Chlorine can be made by oxidation of concentrated HCl with MnO₄ or KMnO4
4. Solution Cl₂ in water obtaioned by reacting CaCl₂.Ca(ClO)₂ or NaOCl with HCl

Application
Fluorine
- Used as fluorinating agent for organic compounds.
Chlorine
- In manufacture of organic and inorganic chemicals, paper and pulp industry, water treatment and also in cleaning and sanitation
Bromine
- Utilized in the manufacture of organic chemicals

Chemical Properties
- As oxidizing agent (high electronegativity)
Displacement reaction
- ability of halogen as oxidizing agent decreases going down the group.

Reaction with H ₂ S
- exception of fluorine, halogen reacts with water in disproportionation reaction
- a reaction undergoes both oxidation and reduction

Reaction with alkali solution
- general disproportionation reaction for Cl, Br and I. (Hypohalite tends to disproportionate further)

Reaction with non-metallic elements
- Halogens form covalent bonds in compounds with non-metallic elements
- aqueous solution of non-metal halides undergoes hydrolysis reactions
(CCl₄ does not hydrolyze)

Reaction with metals
- Halides of s-block metals are ionic
- MX₂ have some covalent character
- Halides of d-block and p-block metals in low oxidation state are ionic
- Halides of d-block and p-block metals in high oxidation state show some covalent character

Compounds of halogen
1. Hydrogen Halides
Industrial preparation
HF - reaction of CaF₂ with H₂SO₄
HX (X = Cl, Br, I) -direct reaction of hydrogen and halogen

Laboratory preparation
- reaction of halide salts with concentrated H₂SO4 (not suitable for the preparation of HBr and HI)
- reaction of phosphoric acid with halide salts in the presence of P₂O₅ (suitable method for preparation HX)

Physical properties
- Thermal stability of HX :
HF > HCl > HBr > HI
- Acid strength of HX :
HF << HCl < HBr < HI

Chemical Properties
- reacts with metals above hydrogen in the Electrochemical Series
- reacts with metal oxides, hydroxides and carbonates
- HF reacts with glass
- HX as reducing agent
HCl < HBr <HI

2. Oxoacid of Halogen

+7 HOXO₃ (Perhalic acid)

+5 HOXO₂ (Halic acid)

+3 HOXO (Halous acid)

+1 HXO (Hypohalous acid)

Preparation
Hypohalous acid, HOX
- Hydrolysis of halogen : disproportionation reaction
- HOX (X = Cl, Br, I) are weak acid
HOCL > HOBr > HOI
- oxidizing agents

Halous acid, HOXO
- only HOClO is important (stable than HOBrO and HOIO)

Ba(OH)₂ + H₂O₂ + 2ClO₂ -> Ba(ClO₂)₂ + 2H₂O + O₂

Ba(ClO₂)₂ + H₂SO₄ -> BaSO₄ + 2HOClO₂

Halic acid, HOXO ₂

-only HOIO2 easily be prepared and isolated from its aqueous solution.

I₂ + 10HNO₃ -> 2HOIO₂ + 10NO₂ + 4H₂O

Perhalic acid, HOXO ₃
- Prepared from the catalytic oxidation of the corresponding halate,XO₃⁻ followed by the addition of a strong acid.

3. Oxyanion and salts of halogen

+1 XO (hypo - ite ion)

+3 XO₂ ( - ite ion)

+5 XO₃ ( - ate ion)

+7 XO₄ (per - ate ion)

Oxides
Cl₂O₆

Red molecule

Preparation - mixture of anhydride chloric and perchloric acid

Cl₂O₇

Dehydrating concentrated perchloric acid with P₂O₅ and distilling product at -35oC, 1mm Hg pressure

I₂O5

White solid

Decompose at temperature higher than 300oC

Preparation - dehydrating iodic acid at 200oC in a stream of dry air

# data[].attributes.headline
NUR AIDA SYAMIMI BINTI AZHAR (A20SC0210)

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NUR AIDA SYAMIMI BINTI AZHAR (A20SC0210)

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Group VIIA Halogen ;
⁃ has 7 valence e
⁃ found as salts of the halide ion due to high reactivity

1. Trend going down the group,
Increase in
⁃ atomic radius
⁃ melting & boiling pt.
⁃ density
⁃ colour intensity

Decrease in
⁃ IE
⁃ Electronegativity
⁃ Oxidizing power

2. Preparation
Industrial
⁃ Fluorine : electrolysis of HF dissolved in molten KF
⁃ Chlorine :
a)electrolysis of NaCl in down cell
b) electrolysis of Brine in Kellner Solvay   method using Chlor-alkali cell
⁃ Bromine : Extreacted by passing chlorine gas into concentrates sea water

Laboratory
⁃ React solution of halide ions with substance that stronger oxidizing agent
⁃ React metal halide with strong oxidizing agent
⁃ Chlorine made by : Oxidation of conc. HCl with MnO2 or KMnO4
⁃ Solution Cl2 in water obtained by reacting bleaching powder/solution

3. Application
⁃ F : Fluorinating agent for organic compounds
⁃ Cl : paper and pulp industry, water treatment, cleaning & sanitation
⁃ Br : manufactuee of organic chemicals

4. Chemical Properties
⁃ Act as oxidizing agent : high electronegativity, gain e.
⁃ React with H2S
⁃ React with water (disproportionation reaction)
⁃ React with alkali solution
⁃ React with non metal
⁃ React with metal

Test to identify halide ions

1. Add conc. H2SO4 and heat
Cl - HCL released
Br - HBr, SO2 & Br2 liberated
I - SO2, H2S and I2 liberated

2. Add AgNO3 + NH3
Cl - White ppt dissolve in NH3
Br - Yellowish-white ppt dissolve in conc. NH3
I - Yellow ppt sparingly dissolve in conc. NH3

3. Add Cl2@NaCIO then CCI4
Cl - no reaction
Br - Br2 released, brown layer CCl4 formed
I - I2 released, pink layer CCI4 formed

Compounds of Halogen

1. Hydrogen Halide, HX
Industrial preparation HF
⁃ reaction of CaF2 with H2SO4
⁃ Direct react hydrogen and halogen (except F)

Laboratory
⁃ react halide salts with conc. H2SO4 ( not suitable for HBr and HI, hyride will oxidize by acid)
⁃ react with H3PO4 with halide salts with the presence of P205, catalyst (more suitable method)

Physical Properties
⁃ Thermal stability decrease down the group
⁃ Acid strength increase down the group

Chemical Properties
⁃ react with metal above Electrochemical series
⁃ react with metal oxide, hydroxides & carbonate
⁃ HF react with glass
⁃ HX as reducing agent (HCl < HBr < HI)

Oxoacid

Hypohalous acid, HOX ( +1 )
⁃ prepared by hydrolysis of halogen (disproportionation)
⁃ weak acid

Halous acid, HOXO (+3)
⁃ prepared by chlorine dioxide + H2S2 + barium hydroxide
⁃ HOCIO more stable than HOBrO & HOIO

Halic acid, HOXO2 (+5)
⁃ Only HOIO2 can be prepared easily

Perhalic acid, HOXO3 (+7)
⁃ HOCIO3 can be prepared by catalytic oxidation
⁃ strong acid and powerfil oxidizing agent

Effect of numbers of oxygen on the acidity :
More O, more acidity

Oxyanion and salts of halogen

1. XO : hypo -ite ion
Prepared by electrolysis of cold brine & reaction of CaO or Ca(OH)2 with chlorine

2. XO2 : -ite ion
Prepared by reaction of ClO2 with NaOH and H2O2

3. XO3 : -ate ion
Prepared by electrolysis of hot brine & oxidation of halide ion(-1) by hypochlorite ion(+1)

4. XO4 : per-ite ion
Used in fireworks

Oxides of Halogen

⁃ CI2O6 : highly unstable red molecule
⁃ I2O5 : white solid compound, poweful oxidizing agent

# data[].attributes.headline
FARHAH NAJIHAH BINTI MAT AZAHAR (A21SC0075)

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FARHAH NAJIHAH BINTI MAT AZAHAR (A21SC0075)

# data[].attributes.body
Group VIIA-Halogens

Trend going down the group
Regular increase in

melting & boiling point

colour intensity

atomic & ionic radius

density of the elements

Decrease down the group

Ionization energy

electronegativity

oxidizing power

Preparation
Industry preparation
Fluorine
-electrolysis of HF dissolved in molten KF
Chlorine
-electrolysis of molten NaCl in Down Cell
-electrolysis of brine in Kellner-solvay/ Chlor-alkali cell
Bromine
-extracted by passing chlorine gas into concentrated sea water

Laboratory preparation
1. reacting a solution of halide ions with substance that is a strong oxidizing agent
2. reaction of metal halide with strong oxidizing agent in presence of acid
3. Cl (made by oxidation of concentrated HCl with MnO2 or KMnO4)
4. solution of Cl2 in H2O obtain by reacting CaCl2. Ca(ClO)2 or NaOCl with HCl

Application
Fluorine- fluorinating agent for organic compound
Chlorine- paper and pulp industry, water treatment, cleaning and sanitation
Bromine- in manufacture of organic chemicals

Chemical Properties
- as an oxidizing agent (ability decrease from F2, Cl2, Br2, to I2)
-react with H2S
-react with water
(dissproportionation except F2)
-react with alkali solution
-react with non- metallic elements (form covalent bonds)
-react with metal

Tests to identify halide ions
1) Add conc. H2SO4 and heat
#Cl →HCl gas released
#Br →HBr, SO2 & Br2 liberated
#I→SO2, H2S and I2 liberated

2) Add AgNO3 followed by NH3
#Cl →white ppt dissolve
#Br → yellowish-white ppt dissolve
# I → yellow ppt, sparingly

3)Add Cl2 or acidic NaClO and then CCl4
#Cl →no reaction
#Br → Br2 released, brown CCl4 layer formed
#I→I2 released, pink CCl4 layer formed

Compounds of halogen
Hydrogen halide
Industrial preparation
HF- reaction of CaF2 with sulphuric acid
HX (X=Cl, Br, I)
-direct hydrogenation halogen

Laboratory preparation
-preparation by reaction chlorine salts with conc. H2S04 (not suitable for HBR and HI, the hydrides will be oxidized by the acid)
-reaction of H3PO4 with halide salt in presence of P2O5 (more suitable method)

Physical properties of HX
-Thermal stability:
HF>HCl>HBr>HI
-Acid strength:
HF<<HCl< HBr < HI

Chemical properties
-react with metals above hydrogen in Electrochemical Series
-react with metal oxide, hydroxides and carbonates
-HF react with glass
-HX is reducing agent (HCl< HBr<HI)

Oxoacid of Halogen
+1 - HXO (hypohalous acid)
-acid strength : HOCl>HOBr>HOI

+3 - HOXO (halous acid)
-HOClO more stable than HOBrO and HOIO

+5 -HOXO2 (halic acid)
-only HOIO2 can be easily prepared

+7 - HOXO3 (perhalic acid)
-strong acid and strong oxidizing agent

Effect of the number of oxygen on acidity of oxoacids:
HOCl<HOClO<HOClO2< HOClO3

Oxyanion and salts of halogen
+1 XO (hypo- -ite ion)
+3  XO2 (-ite ion)
+5 XO3 (-ate ion)
+7 XO4 (per- -ate ion)

Oxides of halogen
-Most of them are unstable

Cl2O6
-high unstable red molecule
-mixture of anhydride of chloric and perchloric acid

Cl2O6
-dehydrating concentrated perchloric acid with P2O5 and distilling (-35 degree celsius under 1mmHg pressure)

I2O5
-White solid
-decompose at temperature >300 C
-preparation: dehydrating ionic acid at 200C in a stream of dry air

# data[].attributes.body
Group VIIA - Halogen
- found as salts of the halide ion
- has 7 valence electron
- diatomic molecules

Trend
Increase down the group
- melting & boiling point
- colour intensity
- atomic & ionic radius
- density of the elements

Decrease down the group
- IE
- electronegativity
- oxidizing power

Industrial preparation
Fluorine - electrolysis of HF dissolved in molten KF
Chlorine - electrolysis of molten NaCl in Down Cell, electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell
Bromine - extracted by passing chlorine gas into concentrated sea water

Laboratory preparation
- solution of halide ions + stronger oxidizing agent
- metal halide + stronger oxidizing agent
- Cl - made by oxidation of concentrated HCl with MnO2 or KMnO₄
- Solution Cl₂ in water by CaCl₂.Ca(ClO)₂ or NaOCl + HCl

Application
F - fluorinating agent for organic compound
Cl - paper and pulp industry, water treatment, cleaning and sanitation
Br - in the manufacture of organic chemicals

Chemical Properties
- as an oxidizing agent (ability decrease from F2, Cl2, Br2 to I2)
- react with H2S
- react with water (disproportionation reaction)
- react with an alkali solution
- react with non-metallic metals element (form covalent bond)
- react with metal

Tests to identify halide ions
Add conc. H2SO4 and heat
Cl- -> HCl gas released
Br- -> HBr, SO2 & Br2 liberated
I- -> SO2, H2S and I2 liberated

Add AgNO3 followed by NH3
Cl- -> white ppt dissolve in NH3
Br- -> yellowish-white ppt dissolve in conc NH3
I- -> yellow ppt, sparingly dissolved in conc NH3

Add Cl2 or acidic NaClO and then CCL4
Cl- -> no reaction
Br- -> Br2 released, brown CCl4 layer formed
I- -> I2 released, pink CCl4 layer formed

Hydrogen Halide, HX
Industrial preparation
HF - reaction of CaF2 with sulphuric acid
HX (X= Cl, Br, I) - direct hydrogenation with halogen

Laboratory preparation
- prepared by reaction chlorine salts with conc. H₂SO₄. (not suitable for HBr and Hl, the hydrides will be oxidized by the acid)
- reaction of H3PO4 with halide salt in presence of P2O5 (more suitable method)

Physical properties
Thermal stability: HF > HCl > HBr > HI
Acid strength: HF << HCl < HBr < HI
HF is a weak acid because F (high electronegativity) doesn't release H easily, needs more energy to break the stronger bonds. Low ability to donate H+, thus weak acid.

Chemical properties
- react with metals above hydrogen in Electrochemical Series
- react with metal oxide, hydroxides, and carbonates
-HF reacts with glass
-HX is a reducing agent (HCl<HBr<HI)

Oxoacid
+1 - HXO (hypohalous acid)
- acid strength: HOCl>HOBr>HOI

+3 - HOXO (halous acid)
- HOClO more stable than HOBrO and HOIO

+5 - HOXO2 (halic acid)
- only HOIO2 can be easily prepared

+7 - HOXO3 (perhalic acid)
- strong acid and strong oxidising agent

Effect of  the number of oxygen on acidity of oxoacids: HOCl < HOClO < HOClO2 < HOClO3

Oxyanion and salts of halogen
+1 - XO- (hypo- -ite ion)
+3 - XO2- ( -ite ion)
+5 - XO3- ( -ate ion)
+7 - XO4- (per- -ate ion)

Oxides
- Most of them are unstable

Cl2O6
- red molecule
- preparation: anhydride chloric + perchloric acid

Cl2O7
- dehydrating concentrated perchloric acid with P2O5 and distilling (-35C ,1 mm Hg pressure)

I2O5
- white solid
- decompose at temperature > 300 C
- preparation: dehydrating ionic acid at 200C in a stream of dry air

# data[].attributes.body
Group VIIA-Halogen

"Hals"-salt,"gennan"-generate.

found as salts of the halide ion-high reactivity.

has 7 valence electrons (ns²np⁵)

form singly bonded diatomic molecules,X₂ - only need one more electron to achieve stable octet electron arrangement.

What increase going down the group? (F<Cl<Br<l<At)

1. melting point and boiling point-increase in Van der Waals forces.

2. colour intensity

3. atomic radius and ionic radius

4. density of the elements.

What decrease going down the group?

1. ionization energy

2. electronegativity

3. oxidizing power (E°SRP)

Anomaly of F

only has 1 oxidation state.

- because of the highest electronegativity, it can easily remove an electron form a nearby atom. (very hard to lose electron)

Industrial Preparation
Fluorine

electrolysis of HF dissolved in molten KF(as electrolyte bcs pure HF is non-conducting molecular compound)

Anode : 2F⁻ → F₂ +2e⁻/ Cathode : 2H+ +2e⁻  →  H₂

Chlorine

1. Electrolysis of molten NaCl in Downs Cell. (produce sodium metal in cathode,need extremely high temperature)

2. Electrolysis of brine in Kellner-Solvay method/Chlor-alkali cell(produce chlorine,H₂ and sodium hydroxide,need room temperature).

Bromine

Passing chlorine gas into conc. sea water.

Cl₂ + 2Br⁻  →  2Cl⁻ + Br₂

Air is passed through the seawater (to vapourize bromine) and tranfer the gas into sulphite, SO₃ ²⁻ solution.

SO₃ ²⁻ + Br₂  →   SO₄ ²⁻ + 2Br⁻

Chorine gas is used to oxidize the Br⁻ back to Br₂ before distilling the pure bromine out.

Laboratory Preparation

1. Reacting a solution of the halide ions with any substance that is stronger oxidizing agent.

2. Reaction of metal halide with strong oxidizing agent such as MnO2 in the presence of acid.

3. Oxidation of conc.HCl with MnO₂ or KMnO₄. (Chlorine only)

4. Reacting bleaching powder,CaCl₂.Ca(ClO)2 or bleaching solution,NaOCl with HCl produced a solution of Cl₂ in water.

Application of Halogen
Fluorine - fluorinating agent for organic compounds, used in polymers,refrigerant fluids,aerosol propellants and non-flammable anesthetics.
Chlorine - used in manufacture of organic and inorganic chemicals, in paper and pulp industry(to bleach the pigment),in water treatment, in cleaning and sanitation.
Bromine - utilized in the manufacture of organic chemicals.

Chemical Properties
Halogens as

oxidizing agents(high electronegativity, tend to gain electrons)

in displacement reaction. The ability of oxidized decrease from F₂ to l₂. But F is rarely used as it is difficult to handle)

Reactions with water

Halogen reacts with water in a disproportionation reaction.

reactants serve as both oxidizing and reducing agents.

But only F₂ and Cl₂ can oxidize water.

Reactions with alkali solution (Cl,Br, and l)

X 2 + 2OH-  → X⁻ + XO⁻ +H₂O

3XO⁻  →  2X⁻ + XO₃⁻

Reactions with non-metallic elements

form covalent bonds

Non-metal halides(aqueous solution) undergo hydrolysis. But CCl4 does not hydrolyze(don't have d orbital to receive a pair of e⁻ from H₂O)

Reactions with metals

halides of s-block metals - ionic.

halides of d-block and p-block metals (low in oxidation state) - ionic, (high oxidation state) - covalent.

Tests to identify halide ions

1. Add conc. H₂SO₄ and heat

Cl⁻ - release HCl gas

Br⁻ - HBr,SO₂ and Br₂ liberated.

l⁻ - SO₂,H₂S and l₂ liberated.

2. Add AgNO₃ followed by NH₃

Cl⁻ - produced white ppt. dissolved in NH3.

Br⁻ - yellowish-white ppt. dissolved in conc.NH₃.

l⁻ - Yellow ppt. sparingly dissolved in conc.NH₃.

3. Add Cl₂ or acidic NaClO and then CCl₄.

Cl⁻ - No reaction

Br⁻ - Br₂ released and formed brown CCl₄ layer.

l⁻ - l₂ released and formed pink CCl4 layer.

Compounds of Halogen

Hydrogen Halides,HX
HF

manufactured industrially by the reaction of fluospar,CaF2 with sulphuric acid at 200-350℃

used in manufacture of aluminium fluoride,boron trifluoride,uranium tetrafluoride and ammonium hydrogen fluoride, in manufacture of fluorohalogen hydrocarbons and in pickling stainless steel.

HX (X=Cl,Br,l)

manufactured industrially by direct reaction of hydrogen and halogen. H₂ + X₂  →  2HX

HCl - used in pickling of metals,acid treatment of oil and gas wells,neutralization in inorganic and organic chemistry,hydrolysis of protein and carbohydrates,manufacture of ClO2.

In lab, prepared by reaction chlorine salts with conc. H₂SO₄. (not suitable for HBr and Hl,the hydrides will be oxidize by the acid).

Can prepared by reacting the phophoric acid and halide salts(Cl,Br,I) in the presence of P₂O₅.

Physical Properties

thermal stability : HF > HCl > HBr > Hl

Acid strength :  HF << HCl < HBr < Hl

High electronegativity difference, bond between F and H is very strong.Hence F does not let got H easily, more energy needed to break the bond.

Chemical Properties

react with metals above H in the Electrochemical series.

react with metal oxides, hydroxides and carbonates.

HF reacts with glass.

Hx as reducing agent.

Oxoacid of Halogen

Fluorine - only formed hypofluorous acid,HOF.

Cl,Br,l - form four types of oxoacid~Perhalic acid(+7),halic acid(+5),halous acid(+3),hypohalous acid(+1)

Hypohalous acid,HOX

by Hydrolysis of halogen(disproportionation reaction)

HOX are weak acid, HOCl>HOBr>HOl

oxidizing agents.

Hydrolysis of dichlorine oxide,Cl₂O (industrial preparation)

Halous acid,HOXO

Chlorous acid,HOClO more stable,prepared by reacting the chlorine dioxide with hydrogen peroxide in the presence of BaOH.Ba(ClO₂)2 precipitated and reacted with H₂SO₄ to release chlorous acid.

Halic acid,HOXO ₂

only HOlO₂ can be easily prepared by reaction of iodine with nitric acid.

Perhalic acid, HOXO ₃

HOClO₃ and HOlO3 can be prepared from the catalytic oxidation of halate,XO₃⁻ followed by the addition of a strong acid.

HOXO₃ are strong acid and powerful oxidizing agent. It oxidizes organic materials explosively when heated.

Evaporation of aqueous HOlO₃ gives crystals of orthoperiodic acid H₅lO₆.

The number of lone oxygen atom attached to central atom affects the acidity of the oxoacids. Number of lone oxygens ↑, oxoacid becomes a better proton donor,

Acid strength of oxoacid oc chlorine :

HOCl < HOClO < HOClO₂ < HOClO₃

Oxyanion and salts of halogen

+1 = hypochlorous acid,ClO⁻ hypochlorite ion
+3 = chlorous acid, ClO₂⁻ chlorite ion
+5 = chloric acid, ClO₃⁻ chlorate ion
+7 = perchloric acid, ClO₄⁻ perchlorate ion

Hypochlorite ions,ClO⁻ (most important)

prepared by electrolysis of cold brine (15℃, Chlor-alkali industry)

1. Anode : 2Cl⁻  →  Cl₂ + 2e⁻

2. Cathode : 2H₂O + 2e⁻  →  H₂ + 2OH⁻

Chlorine gas at anode mixed with hydroxide ion at cathode.

1. Cl₂ + 2OH⁻  →  ClO⁻ + Cl⁻ +H₂O

bleaching solution = NaOCl, sodium hypochlorite solution.

If the solution is hot, reaction produce mixture of chloride and chlorate.

Reaction of CaO or Ca(OH)₂ with chlorine

bleaching powder = mixture of solid CaCl 2 and Ca(ClO)₂

hypochlorite salt used as bleaching agent, oxidizing agent and disinfectants.

Hypohalite ion (in aqueous solution)
*Hypoiodite ion does not exist in solution.

undergo disproportionate reaction.

1. 3XO⁻  →  2X⁻ + XO₃⁻

Rate of reactions, ClO⁻ < BrO⁻ << IO-

Halite ion (+3)

sodium chlorite, NaClO₂ industrially important.

used as bleaching and oxidizing agent,deodorizing agent of odorous industrial emission.

produced by the reaction of ClO₂ with NaOH and H₂O₂.

1. 2ClO₂ + 2NaOH + 2H₂O₂  →  2NaClO₂ + 2H₂O + O₂

if carefully controlled, a mixture of chlorate (+5) and hypochlorite (+1) solution ions can be converted into chlorite (+3) ion solution.

1. ClO₃⁻ + ClO⁻  →  ClO₂⁻

Halate ion (+5)

prepared by electrolysis of hot brine (70℃)

1. 3X₂ + 6OH⁻  →  XO₃⁻ + 5X⁻ +3H₂O

prepared by oxidation of halide ion (-1) by hypochlorite ion (+1) [applicable for preparation of bromate and iodate salt]

NaClO₃-defoliant and herbicide.

KClO₃- primary oxidant in fireworks and matches,source of obtaining oxygen gas in lab experiment(with MnO₂)

1. 2KClO₃  →  2KCl + 3O₂

lO₃⁻,iodates - source for production of iodine.

Perhalate ions

mainly utilized in fireworks.

sodium, potassium, ammonium perchlorates particularly important industrially.
Sodium perchlorate

manufactured from sodium chlorate(+5) by electrochemical synthesis.

1. NaClO₃ + H₂O  →  NaClO₄ + H₂

Potassium and ammonium salts

produced by metathesis with sodium perchlorate.

1. NaClO₄ + MCl  →  MClO₄ + NaCl (M=K,NH₄⁺)

Ammonium perchlorate - used as oxidation agent in rocket fuel.

Oxides of Halogen

mostly unstable.

~ dichlorine hexoxide, Cl₂O₆

solid phase, mixture of anhydride ClO₂⁺ and ClO₄⁻

~ dichlorine heptoxide, Cl₂O₇

~ diiodine pentoxide, l₂O₅

# data[].attributes.body
Halogen
- 7 valence electrons
- diatomic  molecules

Regular increase in

melting & boiling point

colour intensity

atomic & ionic radius

density

Regular decrease in

IE

electronegativity

oxidising power

Industrial Preparation
Fluorine
- electrolysis of HF dissolved in molten KF
Chlorine
- electrolysis of molten NaCl in Down Cell
- electrolysis of brine in Kellner-solvay/ Chlor-alkali cell
Bromine
- extracted by passing chlorine gas into concentrated sea water

Laboratory preparation
1) reacting a solution of halide ions with substance that is a strong oxidising agent
2) reaction of metal halide with strong oxidising agent in presence of acid
3) Cl (made by oxidation of concentrated HCl with MnO2 or KMnO4)
4) solution of Cl2 in H2O obtain by reacting CaCl2.Ca(ClO)2 or NaOCl with HCl

Application of halogen
Fluorine- fluorinating agent for organic compound
Chlorine- paper and pulp industry, water treatment, cleaning and sanitation
Bromine- in manufacture of organic chemicals

Chemical properties of Halogen

oxidising agent (ability decrease from F2, Cl2, Br2 to I2 )

react with H2S

react with water ( disproportionation except F2)

react with alkali solution

react with non-metallic element (form covalent bonds)

reaction with metals

Test to identify halide ions
1)  add conc. H2SO4 and heat
* Cl- (HCl gas released)
* Br- (HBr, Br2, SO2 liberated)
* I- (SO2, H2S, I2 liberated)

2) add AgNO3 followed by NH3
* Cl- (white ppt dissolve)
* Br- ( yellowish-white ppt dissolve)
* I- (yellow ppt dissolve sparingly)

3) add Cl2 or acidic NaClO and then CCl4
* Cl- (no reaction)
* Br- (Br2 released, brown CCl4 layer formed)
* I- (I2 released, pink CCl4 layer formed)

Compounds of Halogen
1) hydrogen halide
Industrial preparation
HF ( reaction of CaF2 with sulphuric acid)
HX (X= Cl, Br, I) direct hydrogenation with halogen

Laboratory preparation
- reaction of halide salts with conc. H2SO4(not suitable to prepare HBr & HI since it will be oxidised by acid)
-reaction of H3PO4 with halide salt in presence of P2O5 (more suitable method)

Physical properties of HX
Thermal stability: HF > HCl > HBr > HI
Acid strength: HF << HCl < HBr < HI

Chemical properties of HX
- react with metals above hydrogen in Electrochemical Series
- react with metal oxide, hydroxides and carbonates
-HF react with glass
-HX is reducing agent (HCl<HBr<HI)

2) Oxoacid of Halogen
HXO (hypohalous acid, +1)
- HOCl>HOBr>HOI (acid strength)
HOXO (halous acid, +3)
- HOClO more stable than HOBrO and HOIO
HOXO2 (halic acid, +5)
- only HOIO2 can be easily prepared ( iodine + nitric acid)
HOXO3 (perhalic acid, +7)
- strong acid and strong oxidising agent

Effect of  the number of oxygen on acidity of oxoacids
- number of lone oxygen increase, oxoacid become better proton donar (stronger acid)
HOCl< HOClO<HOClO2<HOClO3

3) oxyanion and salts of halogen
ClO- (hypochlorite ion, +1)
ClO2- (chlorite ion, +3)
ClO3- ( chlorate ion, +5)
- prepared by electrolysis of hot brine
ClO4- (perchlorate ion, +7)

4) Oxides of halogen
* Cl2O6
- highly unstable red molecules
- mixture of anhydride of chloric and perchloric acid
* Cl2O7
- dehydrating concentrated perchloric acid with P2O5 and distilling ( -35 degree celsius under 1mmHg pressure)
* I2O5
- white solid compound
- decompose at temperature > 300 degree celsius
- dehydrating iodic acid at 200 degree celsius in a stream of dry air
- powerful oxidising agent

# data[].attributes.body
GROUP VIIA - HALOGEN

Trend
Increase down the group

Melting point & boiling point

Color intensity

Atomic and ionic radius

Density

Decrease down the group

Ionization energy

Electronegativity,  F<Cl<Br<I<At

Oxidizing power

Preparation
Industrial
1) Fluorine

Electrolysis of HF

2) Chlorine

Electrolysis of NaCl (Down Cell)

Electrolysis of brine in Kellner-Solvay method or Chlor-alkali cell

3)Bromine

Passing Cl₂ gas into concentrated sea water

Laboratory
1) Solution of halide ions + any substance that is stronger oxidizing power
2) Metal halide + strong oxidizing agent
3) Cl can made by oxidation of conc. HCl with MnO2 or KMnO₄
4) Solution Cl₂ in water by CaCl₂.Ca(ClO)₂ or NaOCl + HCl

Application
1) Fluorine
- Used as fluorinating agent for organic compounds.
2) Chlorine
- in manufacture of organic and inorganic chemicals, paper and pulp industry, water treatment,cleaning and sanitation
3) Bromine
- mainly utilized in manufacture of organic chemicals

Chemical Properties
Displacement reaction

Ability of halogen as oxidizing agent decrease down the group.

Reaction with H ₂ S

X2 + H₂S --> 2HX + S   (X=Cl, Br, I)

Reaction with water

Except F, halogen react with water in disproportionation reaction (undergo both oxidation and reduction).

Reaction with alkali solution

General disproportionation reaction for Cl,Br and I. Hypohalite (XO⁻) tend to disproportionate further.

Reaction with non-metallic element

Halogen form covalent bond in compound with non-metallic element.

Aqueous solution of non-metallic halide undergo hydrolysis reaction.

CCl₄ does not hydrolyze because C has no d orbital to receive a pair of electron from water molecule.

Reaction with metal

Halide of s-block metals are ionic

MX₂ have some covalent character

Halide of d-block and p-block metals in low oxidation state are ionic and in high oxidation state show some covalent character

Hydrogen Halides, HX
Industrial preparation

H₂ + X₂ —> 2HX

Laboratory preparation

2NaX+H₂SO₄ —> Na₂SO₄ + 2HX (X=Cl, Br, I)

2HX+ H₂SO₄ —> 2H₂O + SO₂ + X₂        (X= I, Br)

3KX+ H₃PO₄ —>K₃PO₄+ 3HX     (X=Cl, Br, I)

Physical properties

Thermal stability: HF>HCl>HBr>HI

Acid strength: HF<<HCl<HBr<HI            (The more easier the H+ can be released ,the higher the acidity )

HF is a weak acid due to the small size and high electronegativity of F, the bond between F and hydrogen is very strong. They have a very high electronegativity difference. That is why F doesn't  let go hydrogen easily, more energy needed to break the bond.

Chemical properties

React with metals above hydrogen in electrochemical series

React with metal oxides, hydroxides and carbonates

HX as reducing agent

Strength as reducing agent              HCl< HBr < HI

Oxoacids
Oxidation number

+7 HOXO₃ Perhalic acid -highest oxidation number

+5 HOXO₂ Halic acid

+3 HOXO Halous acid

+1 HXO Hypohalous acid -lowest oxidation number

Preparation
Hypohalous acid, HOX

Disproportionation reaction

Halous acid, HOXO

Ba(OH)2 + H₂O2 + 2ClO2 -->Ba(ClO₂)₂ + 2H₂O + O₂

Ba(ClO₂)₂+H₂SO₄ --> BaSO4 + 2HClO₂

Halic acid, HOXO ₂

I2 + 10HNO3 --> 2HOIO2 + 10NO2 + 4H₂O

Perhalic acid, HOXO ₃
Prepared form catytuc oxidation of the corresponding halate,XO₃- followed by addition of strong acid

Effect number of oxygen on the acidity of oxoacids
The higher the number of lone oxygens, the stronger the acid.
HOCl<HOClO<HOClO₂<HOClO3

Oxyanion and salt of halogen
Hypochlorite ion(+1)
ClO⁻ < BrO⁻ << IO⁻

Hypobromite salt unstable

Hypoiodite ion doesn't exist

Hypochlorite salt used as bleaching agent,oxidizing agent and disinfectant

Preparation

Electrolysis of cold brine

CaO/CA(OH)₂ with chlorine

Halite ion(+3)

Only NaClO₂ industrially important

Salt used as bleaching and oxidizing agent

Salts produced by reaction of ClO2  with NaOH and H₂O₂

Halate ion(+5)
Preparation
1) Electrolysis of hot brine
2) oxidation of halide ion by hypochlorite ion.
Perhalate ion (+7)

NaClO₃ + H₂O --> NaClO₄ + H₂

Potassium and ammonium salt produced by: NaClO₄ + MCl --> MClO₄ + NaCl     (M= K,NH₄⁺)

Oxides
Cl ₂ O ₆

Red molecule

Preparation; anhydride chloric + perchloric acid, ClO₂⁺ & ClO₄⁻

Cl ₂ O ₇

Dehydrating concentrated perchloric acid with P2O5 and distilling (-35C ,1 mm Hg pressure)

I ₂ O ₅

White solid

Decompose at temperature > 300 C

Preparation: dehydrating ionic acid at 200C in a stream of dry air     I₂O₅+5CO —> I₂ + 5CO₂

# data[].attributes.body
-diatomic molecules
-has 7 valence electrons
-found as salt of halide ions because of their high reactivity (Cl-, Br-, I-)
-need only one electron to achieve a noble gas configuration

Regular in increase in
• melting point & boiling point - caused by the increase in van der Waals forces (London dispersion force))
• colour intensity
• radius & radius
• density of the elements.

Regular decrease in
• Ionization energy
• oxidizing power

Fluorine-colourless
Chlorine-yellowish green gas
Bromine-reddish brown liquid
Iodine-violet

Why F has 1 oxidation state?
-has the electronic configuration 1s2 2s2 2p5
- needs 1 electron to fulfill octet
- has the highest electronegativity among all the elements
-can easily remove an electron from a nearby atom

Industrial Preparation
Fluorine
-obtained by electrolysis of HF dissolved in molten KF

Chlorine
-electrolysis of molten NaCl in Downs Cell
( at high temperature)
-electrolysis of brine in Kellner-Solvay method ( room temperature)
-Chlor-alkali cell

Bromine
-passing chlorine gas into concentrated sea water

Laboratory Preparation
-reacting a solution of halide ions with any substance that is a stronger oxidizing agent
-reaction of metal halide with strong oxidizing agent such as MnO2 in the presence of acid
-chlorine can be made by oxidation of concentrated HCl with MnO2 or KMnO4
-a solution of Cl2 in H2O is obtained by reacting bleaching powder, CaCl2.Ca(ClO)2 or bleaching solution, NaOCl with HCl.

Halogen as oxidizing agent
-Because of high electronegativity of halogen compared to other elements, they tend to gain electrons from other substances and thereby serves as oxidizing agents.

(a) Displacement reaction
From the values of E0 SRP, electron affinity and electronegativity. the ability of halogen as oxidizing agent decrease going down the group. F2 > Cl2 > Br2 > I2
F2 will oxidize Cl− , Br− and I− ions.
F2 (g) + 2X− (aq) → X2 (g) + 2F− (aq) ……(X= Cl, Br, I)

Cl2 will oxidize Br− and Cl2 (aq) + 2X− (aq) → X2 (aq) + 2Cl− (aq) …..(X = Br, I)

Br2 will oxidize I− ion Br2 (aq) + 2I− (aq) → I2 (aq) + 2Br− (aq)

-halogen undergo disproportionation reaction when react with water. It is a specific type in which an element undergoes both oxidation and reduction to form two different products.

Hydrogen halide
-manufactured industrially by the reaction of fluorspar (acidspar), CaF2 with sulphuric acid at 200 – 350 °C.
-by direct reaction of hydrogen and halogen
-reaction of halide salt with concentrated sulfuric acid
-reaction of concentrated phosphoric acid with halide salts in the presence of P2O5.
- thermal stability of HX : HF>HCl>HBr>HI
-acid strength of HX: HF<<HCl<HBr<HI

Why HF is a weak acid?
Due to the small size and high electronegativity of fluorine, the bond between fluorine and hydrogen is very strong.They have a very high electronegativity difference. That is why fluorine doesn't hydrogen let go easily, needs more energy to break the bond. So extent of donating hydrogen ion in is low in HF that is why it is considered weak acid.

Oxoacid
Oxidation number
- +7 HOXO3 Perhalic acid
- +5 HOXO2 Halic acid
- +3 HOXO Halous acid
- +1 HXO Hypohalous acid (*HFO instable)
Hypo - lowest oxidation no.
Per - highest oxidation no.

Effect number of oxygen on the acidity of oxoacids
The higher the number of lone oxygens , the stronger the acid.
HOCl<HOClO<HOClO2<HOClO3
Oxygen is a very electronegativite element and has a strong tendency to pull electron density away form any atom which is attached. In oxoacid, more lone oxygen pull electron density from central atom, more polar will be the O-H bond, more easier released hydrogen ion, thus the acidity increases.

Oxyanion and salts of hydrogen
+1 hypochlorite ion,ClO-
+3 chlorite ion,ClO2-
+5 chlorate ion,ClO3-
+7 perchlorate ion,ClO4-

Oxides of Halogen
Dichlorine hexoxide (Cl2O6)
-highly unstable molecule.

Dichlorine heptoxide (Cl2O7)
-prepared by carefully dehydrating concentrated perchloric acid with P2O5 and distilling the product at –35 °C under 1mm Hg pressure.

Diiodine pentoxide (I2O5)
-white solid compound
-decomposes only at temperature higher than 300 °C
-prepared by dehydrating iodic acid at 200 °C in a stream of dry air

# data[].attributes.body
Halogen
7ve-, mostly found in salts due to high reactivity

Electronegativity
F,<Cl<Br<I <At

Trend down the group
Increase
mp and bp (VDW force) colour atomic & ionic rad density
Decrease
IE Oxidizing electronegativity

Preparation
INDUSTRIAL
F - electrolysis of HF
Cl - electrolysis of Nacl
Br - pass Cl2 into con. sea water

Application
F - fluorinating agent for organic compounds
Cl - bleaching, water treatment
Br - manufacture of organic compounds

Chem properties
- oxidizing agent etc displacement reaction
-H2S reaction
-Disproportionation reaction etc react with water/alkali
- Hydrolysis reaction etc non -metallic element reaction (except CCl4)

Test for halide ions
- h2So4 conc. test
- AgNO3 follow by NH3
- Cl2 / NaClO then CCl4

Compounds

Hygrogen halides (HX)
Acid Strength
HF<HCl<HBr<HI
Reducing strength
Hcl<HBr<HI
Chem Properties
- react with oxides, hydroxides and carbonates
Oxidation no
+7 perhalic +6 Halic +3 Halous +1 Hypohalous
Properties
Hypohalous HOX
- weak acid , oxidizing agent
Halous acid, HOXO
HOCLO important cuz stable
Halic HOXO2
HOIO2 imporatnt cuz easily prepared
Perhalic acid HOXO3
strong acid , strong oxidizing agent

Oxyanion and salt
Hypochlorite
- ClO- (bleaching , oxidizing,disinfectant)
Halite
- NaClO2 (bleaching)
Halate
- NaClO3 (defoliant and herbicide)
- KClO3 (fireworks, O2 as source)
Perhalate
-Na K NH3 (ClO3) important
(fireworks)

Oxides
- Nonthing can be summarize

# data[].attributes.body
Halogen
-valence electron: 7 (need 1 electron to achieve octet)
natural occurrence
found as salts of the halide ion because of high reactivity
Fluorine - Fluospar, cryolite, fluoroapatite
Chlorine - Rock salt, sylvite, ocean, great salt lake in Utah
Bromine - ocean
Iodine - ocean, natrium iodate together with chile saltpetre

Physicochemical properties
electronegative
F < Cl < Br < I < At
oxidation
F -1
Cl, Br, I -1 ➡️ +7
At -1,+1,+5

Trend
increase
-melting point and boiling point (increase Van der Waals)
-colour intensity
-atomic & ionic radius
-density of element
decrease
-ionization energy
-electronegativity
-oxidizing power

F only 1 oxidation state because F (high electronegativity) can easily remove electron from nearby atom to fulfill octet.

Industrial Preparation
Fluorine - Electrolysis of HF dissolved in molten KF
Chlorine
-Electrolysis of molten NaCl in Down Cell
-Electrolysis of brine in Kellner-Solvay method or using Chlor-alkali cell
Bromine - extracted by passing Cl2 gas into conc. sea water

Laboratory preparation
1.solution of halide ions + any substance that is stronger oxidizing power
2. metal halide + strong oxidizing agent
3. Cl can made by oxidation of conc. HCl with MnO2 or KMnO4
4. Solution Cl2 in water by CaCl2.Ca(ClO)2 or NaOCl + HCl

Application of Elemental Halogen
Fluorine - used as fluorinating agent for organic compounds.
Chlorine - in manufacture of organic and inorganic chemicals, paper and pulp industry, water treatment,cleaning and sanitation
Bromine - mainly utilized in manufacture of organic chemicals

Chemical properties
Halogen as oxidizing agent (high electronegativity) tend to get electrons
a) displacement reaction
Ability of halogen as oxidizing agent decrease down the group
*F rarely used as oxidizing agent because it is difficult to handle
b) reaction with H2S
X2 + H2S ➡️ 2HX + S
c) reaction with water
Except F, halogen react with water in disproportionation reaction (undergo both oxidation and reduction)
d) reaction with alkali solution
General disproportionation reaction for Cl,Br and I. Hypohalite (XO-) tend to disproportionate further
e) reaction with non-metallic element
Halogen form covalent bond in compound with non-metallic element
Aqueous solution of non-metallic halide undergo hydrolysis reaction
*CCl4 does not hydrolyze because C has no d orbital to receive a pair of electron from water molecule
f) reaction with metal

Halide of s-block metals ➡️ ionic
MX2 ➡️ covalent character
Halide of d-block and p-block metals
-in low oxidation state ➡️ ionic
-in high oxidation state ➡️ some covalent character

Test to identify halide ions
1) add conc. H2SO4 and heat
Cl- HCl gas released
Br- HBr,SO2 and Br2 liberated
I- SO2,H2S and I2 liberated

2) add AgNO3 followed by NH3
Cl- white ppt., dissolve in NH3
Br- yellowish-white ppt., dissolve in conc.NH3
I- yellow ppt.,sparingly dissolve in conc. NH3

3) add Cl2 or acidic NaClO then CCl4
Cl- no reaction
Br- Br2 released, brown CCl4 layer formed
I- I2 released, pink CCl4 layer formed

👉Compound of Halogen👈
⭐1. Hydrogen Halides(HX)
Industrial preparation
HF - CaF2 + H2SO4
HX (Cl,Br,I) direct reaction of hydrogen and halogen

Laboratory preparation
-Reaction of halide salt with conc. H2SO4
*not suitable for preparation HBr and Hl,some hydride will oxidize by acid
-more suitable method👇
H3PO4 (poor oxidizing agent) + halide salts in the presence of P2O5

Acid strength
HF << HCl < HBr < HI
HF is weak acid because F (high electronegativity) don't let go H easily, need more energy to break bond. Low ability to donate H+, thus weak acid

Chemical properties of hydrogen Halides
-react with metals above hydrogen in electrochemical series
-react with metal oxides, hydroxides and carbonates
-HF react with glass
-HX as reducing agent
Strength as reducing agent
HCl< HBr < HI

⭐2) Oxoacid of Halogen
Cl, Br and I form 4 types of oxoacid
F form only 1 ( hypofluorous acid, HOF) bcz it's extremely difficult to oxidize it

Oxidation number
- +7 HOXO3 Perhalic acid
- +5 HOXO2 Halic acid
- +3 HOXO Halous acid
- +1 HXO Hypohalous acid (*HFO instable)
Hypo - lowest oxidation no.
Per - highest oxidation no.

Preparation
i) Hypohalous acid, HOX
hydrolysis of halogen (disproportionation reaction)
ii) Halous acid, HOXO
Ba(OH)2+H2O2+2ClO2 ➡️Ba(ClO2)2+2H2O+O2
Ba(ClO2)2+H2SO4 ➡️BaSO4+2HClO2
iii) Halic acid,HOXO2
I2+10HNO3➡️2HOIO2+10NO2+4H2O
iv) Perhalic acid,HOXO3
Prepared form catytuc oxidation of the corresponding halate,XO3- followed by addition of strong acid

Properties
Hypohalous acid, HOX
- weak acid (weaker than acetic acid)
- HOCl>HOBr>HOI
- oxidizing agent
- industrial preparation
Cl2O + H2O ➡️ 2HClO

Halous acid, HOXO
Only chlorous acid,HOClO important bcz more stable than HOBrO and HOIO

Halic acid, HOXO2
Only HOIO2 (iodic acid) can easily be prepared and isolated from its aqueous solution

Perhalic acid, HOXO3
-strong acid and powerful oxidizing agent
-perchloric acid oxidizes organic material explosively when heated
-evaporation of aqueous solution of periodic acid give crystal orthoperiodic acid,H5IO6

Effect number of oxygen on the acidity of oxoacids
The number of lone oxygens ⬆️, better proton donor(stronger acid)
HOCl<HOClO<HOClO2<HOClO3
Oxygen (very electronegativity) has strong tendency to pull electron away form any atom which is attached. In oxoacid,more lone oxygen pull electron density from central atom, more polar will be the O-H bond, more easier released hydrogen ion,increase acidity

⭐3) oxyanion and salt of halogen
(+1,+3) oxyanion of halogens end with -ite
(+5,+7) oxyanion of halogens end with -ate

+1 hypochlorite ion,ClO-
+3 chlorite ion,ClO2-
+5 chlorate ion,ClO3-
+7 perchlorate ion,ClO4-

Hypochlorite ion(+1)
Only Hypochlorite ion,ClO- and it's salt
Preparation
1) Electrolysis of cold brine
2) CaO/CA(OH)2 with chlorine

rate of reaction
ClO- < BrO- << IO-
-hypobromite salt unstable
-Hypoiodite ion doesn't exist
-Hypochlorite salt used as bleaching agent,oxidizing agent and disinfectant

Halite ion(+3)
-Only NaClO2 industrially important
-Salt used as bleaching and oxidizing agent
-Salts produced by reaction of ClO2 with NaOH and H2O2

Halate ion(+5)
Preparation
1) Electrolysis of hot brine
2) oxidation of halide ion by hypochlorite ion. (Applicable for preparation bromate and iodate salt)

-NaClO3 as defoliant and herbicide,converted to ClO2 - used as bleaching agent for paper pulp
-KClO3 as primary oxidation in fireworks and matched, as a source of obtaining oxygen gas in lab experiment
-Iodates,IO3- as a source for production of iodine

Perhalate ion (+7)
-(Na,K,NH3)ClO3 important industrially
NaClO3 + H2O ➡️ NaClO4 + H2
-Potassium and ammonium salt produced by
NaClO4 + MCl ➡️ MClO4 + NaCl
(M= K,NH4+)
-Perchlorate mainly used in fireworks

⭐4)o xides of Halogen
Cl2O6 - highly unstable red molecule
mixture of anhydride chloric and perchloric acid
Cl2O7 - prepared by careful dehydrating conc. Perchloric acid with P2O5 and distilling product at -35C under 2mmHg pressure
I2O5 - white solid compound, decompose at temperature >300C , prepared by dehydrating iodic acid at 200C in a steam of dry air

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NUR AFIQAH BINTI AHMAD RUSLI (A21SC0210)

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NUR AFIQAH BINTI AHMAD RUSLI (A21SC0210)

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HALOGENS
- halogen atom only has 7 valence electron
- need one electron to achieve octet
- is a very electronegative group compared to other groups
- is a diatomic molecules in their elemental state
GOING DOWN THE GROUP
- increase in melting and boiling point because the van der waals forces also increases
- colour intensity increases
- atomic and ionic radius increases
- density of the elements increases
- ionization energy decreases
- decreases in electronegativity
- oxidizing power decreases
COMPOUNDS OF HALOGEN
Oxoacids of halogen
- Cl, Br and i can form 4 types of oxoacids
- F only can form one type of oxoacid but still in an unstable condition
- suffix hypo is for the lowest oxidation number
- suffix per is for the highest oxidation number
- oxidation number : +7
general formula : HOXO3
general name : perhalic acid
- oxidation number : +5
general formula : HOXO2
general name : halic acid
- oxidation number : +3
general formula : HOXO
general name : halous acid
- oxidation number : +1
general formula : HXO
general name : hypohalous acid
i) hypohalous acid (+1) HOX
- hydrolysis of hydrogen :   disproportionation reaction ( redox )
X2(g,l,s) + H2O(l) --> H+ + X^-(aq) + HOX(aq)
- HOX (X = Cl, Br, I) are weak acid
- HOCl>HOBr>HOI
- oxidizing acids
- prepare by hydrolysis of cidhlorine oxide
ii) halous acid (+3) HOXO
- only chlorous acid is stable compared to bromous acid and iodous acid
- chlorous acid prepared by reaction of chlorine dioxide with hydrogen peroxide
- barium chlorite precipitated then will react with H2SO4 and produce the chlorous acid
iii) halic acid (+5) HOXO2
- only iodic acid can be easily prepared
- it is prepared by reaction of iodine with nitric acid
- I2(aq) + 10HNO3(aq) --> 2HOIO(aq) 10NO2(g) + 4H2O(l)
iv) perhalic acid (+7) HOXO3
- perchloric acid and periodic acid can be prepared by catalytic oxidation of the corresponding halate, XO3^- followed by a strong acid
- perhalic acid are strong acid and powerful oxidizing agent
- evaporation of aqueous solution of periodic acid gives crystals of orthoperiodic acid, H5IO6
- the higher the number of the lone oxygens of the oxoacids, the stronger the acid
- HOCl<HOClO<HOClO2<HOClO3
- the higher the number of double bond O around the Cl, the stronger the acid

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HALOGENS
-found as salts of the halide ion
-7 valence electrons
-get 1 electron achieve noble gas configuration
-diatomic
Down to the group:
Increase:
👉melting point & boiling point (increase in Van der Waals forces )
👉colour intensity
👉atomic and ionic radius
👉density

Decrease:
👉Ionization energy
👉electronegativity
👉oxidizing power

🌟FLUORINE🌟
-only has 1 oxidation state because it has the highest electronegativity
-Obtained by an electrolysis of HF dissolved in molten KF( obtained from anode)

🌟Chlorine🌟
-Electrolysis of molten NaCl in Downs Cell
-Electrolysis of brine in Kellner-Solvay/ Chlor-alkali cell
-Electrolysis of NaCl

🌟Bromine🌟

-stronger oxidizing agent
-preparation:
👉Cl2+2Br- —> 2Cl- + Br2
👉2Br- + Cl2 —> Br 2 + 2Cl-

⛅️
👉4MX + 4H2SO4 + MnO2 —> 4MHSO4 + MnX2 + 2H2O + X2  ( M =Na ,K),(X=Cl,Br,I)
⛅️

🌟
Application of Halogen:
-Fluorine:fluorinating agent for organic compounds
-Chlorine:bleach the pigment,water treatment,cleaner
-Bromine:mainly used in the manufacture of organic chemicals

🌟

CHEMICAL PROPERTIES OF HALOGEN
-oxidizing agent( ability decreases down the group)
-F2 oxidize Cl-,Br-,I-
-Cl2 oxidize Br- ,I-
-Br2 oxidize I-
-React with H2S
X2+H2S —> 2HX + S
-React in water ( disproportionation reaction- one element undergoes oxidation and reduction to form 2 different products)
X2 + H2O —> HOX + H+ + X-

-React with alkali solution:
X2 + 2OH- —> X- + XO- + H2O

-Form covalent bonds with non-metal
-Aqueous solution of non-metal halides undergo hydrolysis

-Reaction of metals:
s-block :ionic
Be and Mg: some covalent character
d-block and p-block (low oxidation state-ionic,high oxidation -some covalent character)

🌟Tests to identify halide ions🌟
1)Add conc.H2SO4 and heat
Cl-:HCl gas released
Br- : HBr,SO2,Br2 liberated
I- : SO2,H2S,I2 liberated

2)Add AgNO3 followed by NH3
Cl-:white precipitates dissolve in NH3
Br-:Yellowish-white precipitates dissolve in conc.NH3
I-:Yellow precipitates sparingly dissolve in conc.NH3

3)Add Cl2(aq) /acidic NaClO(aq) and then CCl4
Cl- : No reaction
Br-:Br2 released.Brown CCl4 layer formed
I-: I2 released.Pink CCl4 layer formed

🌟Compounds🌟
🌸Hydrogen Halides HX🌸
🌈HF
👉Preparation: (200-350 C)
CaF2 + 2H2SO4 —> 2HF + Ca(HSO4)2
👉Application:
-Glass etching and polishing
-Semiconductor manufacture

🌈HCl,HBr,HI
Preparation:
👉 industrial:
H2 + X2 —> 2HX
👉lab:
1. 2NaX+H2SO4 —> Na2SO4 + 2HX (X=Cl,Br,I) (not suitable for prepare HBr and HI)
2. 2HX+ H2SO4 —> 2H2O + SO2 + X2 (X= I,Br)
3.  3KX+ H3PO4 —>K3PO4+ 3HX (X=Cl,Br,I)

Physical properties :
-Thermal stability:HF>HCl>HBr>HI
-Acid strength: HF<HCl<HBr<HI
( The more easier the H+ can be released ,the higher the acidity )

Chemical properties:
-React with the metal above H in the Electrochemical Series
-React with metal oxides,hydroxides and carbonates
-HF reacts with glass
6HF+SiO2 —> H2SiF6 + 2H2O
-HX reducing agent(HCl<HBr<HI)

🌸OXOACID🌸

1.  + 7 ,HOXO3,Perhalic acid
2. +5,HOXO2,Halic acid
3. +3,HOXO,Halous acid
4. +1,HXO,Hypohalous acid

___HXO___
Preparation:
— X2 + H2O —> H+ + X- + HOX

Properties:
-Weak acid ( HOCl >HOBr >HOI)
-Oxidizing agent

__HOXO__
-Only HOClO is important because more stable

Preparation:
Ba(OH)2 + H2O2 + 2ClO2 —> Ba(ClO2)2 + 2H2O + O2

Ba(ClO2)2 + H2SO4 —> BaSO4 + 2HClO2

__HOXO2__
-Only HOIO2 can easily prepared

Preparation:
I2+ 10HNO3 —> 2HOIO2 + 10NO2 + 4H2O

__HOXO3__
-Strong acid and powerful oxidizing agent
-HOClO3 and HOIO3 are prepared by the catalytic oxidation of the corresponding halate XO3- followed by adding strong acid

📝
No of lone oxygens attached to the same central atom increases,acidity of oxoacid increases

Reason:Oxygen is very electronegative,(lone oxygen)it pull electron density toward itself ,ability of central atom pull electron density from O-H bond increases, O-H bond more polarised ,H+ more easier to be released,acidity increases.

📝

🌸OXYANION🌸
- -ite (+1,+3)
- -ate (+5,+7)
- hypo-lowest oxidation no
- per - highest oxidation no

Important:ClO- and its salts
1. Electrolysis of COLD 15C🥶 brine( avoid the formation of ClO3 )
2. Reaction of CaO / Ca(OH)2 with chlorine
Rate of reaction ClO- <BrO-< < IO-

🌟 hypobromite salt unstable
🌟hypoiodite ion does not exist in solution
🌟hypochlorite salt : used as bleaching agent,oxidizing agent, disinfectants

NaClO2
-industrially important
-used as bleaching and oxidizing agent
-Preparation: 2ClO2 + NaOH+ H2O2–> 2NaO2 + 2H2O + O2

🌸Halate ion (+5) and its salts🌸
-Preparation:
1) Electrolysis of hot brine
3X2 + 6OH- —> XO3- + 5X- + 3H2O
2)Oxidation of halide ion (-1) by hypochlorite ion (+1) 👉applicable for preparation of bromate and iodate salt
X- + 3ClO- —> XO3- + 3Cl-  (X=Br,I)

Uses:
1)NaClO3 - bleaching agent for paper pulp
- defoliant and herbicide
2)KClO3 - primary oxidant in fireworks and
matches
- produce oxygen

3)Iodates IO3- -produce iodine

🌸Perhalate ions and its salts🌸
-NaClO4,KClO4, NH4ClO4 are important in industry
-NaClO4
preparation: electrochemical synthesis
NaClO3 + H2O —> NaClO4 + H2

-KClO4, NH4ClO4
preparation:meta thesis with sodium perchlorate
NaClO4 + MCl —> MClO4 + NaCl

🌸OXIDES 🌸
-Most of them are unstable
-Cl2O6
👉red molecule
👉preparation:anhydride chloric + perchloric acid

-Cl2O7
👉dehydrating concentrated perchloric acid with P2O5 and distilling (-35C ,1 mm Hg pressure)

-I2O5
👉white solid
👉decompose at temperature > 300 C
👉preparation: dehydrating ionic acid at 200C in a stream of dry air

I2O5+5CO —> I2 + 5CO2