# data[].attributes.body
Today i learnt about testing for carbonyl compounds and the IR spec

IR spectography
Alcohol: (ghost) 3400, 3000 (two small peaks)
Carboxylic acid: broad 3000, Sharp 1759
Ester: sharp 3000, Sharp 1759

Testing for carbonyl compound

-2,4-dnph-no need to heat-deep orange ppt (both aldehyde and ketone)

-tollen reagent(silver mirror test) -warmed in water bath. Silver mirror formed ( only with aldehyde)

-fehling's solution-warmed in water bath. Brick red ppt is formed ( only with aldehyde)

-Triiodomethane test (ch3co or ch3choh)
Warmed and give yellow ppt

# data[].attributes.body
I learned that there are 4 different reactions involving carbonyl compounds:

1. tollent reagent/fehling’s solution
silver mirror formed (tollent), red ppt formed  (warmed with water bath, fehling’s solution)

2. using 2,4-DNPH
deep orange precipitate formed

3. tri-iodomethane
*warmed
yellow ppt formed

——
I also learned about IR spectroscopy and the graphs that will be produced

- Alcohol: upside down ghost with peace sign, broad at 3400, sharp at 3000
- carboxylic acid: broad at 3000, sharp at 1750
-ester: sharp at 3000, 1750

# data[].attributes.body
I learned about
- The oxidation and reduction of primary/secondary alcohol/ carboxylic acid
- the different oxidation/reducting agent and their colour change
- tollen reagent/fehlings reagent and their visual change for positive test
- 2,4 DNPH
- triodomethane test
- IR spectrospocy and how to read  and special IR graph to identify ester/acid/alcohol

# data[].attributes.body
I relearnt that we can oxidize primary alcohols to aldehydes by adding the oxidizing agents drop by drop or adding in excess to immediately oxidize them to carboxylic acids.
I also learnt that the secondary alcohols can be oxidized to ketones

Reducing the carbonyl compounds requires LiAlH4 or NaBH4 which can reduce carboxylic acid back to a primary alcohol or a ketone to secondary alcohol.

I also learnt of Tollens', Fehling's, 2-4 DNPH and Iodomethane to identify carbonyl compounds which provide a silver mirror for Tollens' and orange precipitate for 2,4 DNPH

# data[].attributes.body
The carbonyl compounds include aldehyde and ketone.

When it ends with CHO it is aldehyde. When it is R1COR2 it is ketone.

Primary alcohol will be oxidised to aldehyde and further oxidised to carboxylic acid. Secondary alcohol will be oxidised to ketone but cannot be oxidised further. Tertiary alcohol cannot be oxidised.

When aldehyde needs to be reduced to primary alcohol or when ketone needs to be reduced to secondary alcohol, reducing agents such as NaBH4

# data[].attributes.body
Tests with Tollen's reagent:
- Test for aldehyde
- Silver mirror precipitate will be present if aldehyde is present

Test with 2,4 DNPH:
- Test for aldehyde and ketone
- Orange precipitate will be present if aldehyde or ketone is present

Test with Fehling's solution:
- Test for aldehyde
- Blue precipitate will be present if aldehyde is present

Infra-red spectometry:

-Alcohol
-"Ghost with peace sign"
-Drops at 3000 and 3400

-Ester
-"Icicles"
-Drops at 1750 and 3000

-Carboxylic acid
-first drop is not as sharp followed by a sharp drop
-Drops at 1750 and 3000

# data[].attributes.body
In order to test for carbonyl compounds, we have 4 methods.

1. Using 2,4-dnph: Deep orange ppt formed for both aldehyde and ketone
Conditions: no need to heat

2. Using Tollen reagent: (silver mirror test) Silver mirror formed only with aldehyde
Conditions: Warmed in water bath.

3. Using fehling's solution: Brick red ppt is formed only with aldehyde
Conditions: warmed in water bath.

4. Tri-iodomethane test (ch3co or ch3choh):
Warm it and it will give yellow ppt

IR spectography
Alcohol: (ghost) 3400, 3000 (two small peaks)
Carboxylic acid: broad 3000, Sharp 1759
Ester: sharp 3000, Sharp 1759

# data[].attributes.body
Today, we again revised on a crucial subtopic of organic compounds, the carbonyl group. We learnt how to prepare Aldehydes by reacting primary alcohols and K2Cr2O7 and KMnO4 drop by drop as well as distilling them immediately. Otherwise, they will further oxidize to form carboxylic acids. To form ketone, we use the same oxidizing agents but with secondary alcohol. We also learnt about the reactions of these carbonyl compounds. They will give a deep orange ppt with 2,4 DNPH. However, only aldehydes will give a positive result with Tollen's reagent, Fehling's reagent, warm K2Cr2O7 and KMnO4. It will form a silver mirror with Tollen's reagent and will change Fehling's reagent from blue to red. Another reaction is the Nucleophilic Addition of Carbonyl compounds. They will react with NaCN to form nitriles. There is once again the curly arrow diagram for this one that we need to thoroughly observe. Reduction can also occur with these Carbonyl compound. The reagents are LiAlH4 in dry ether and NaBH4. Other than that, we also learnt about the IR spectroscopy.

# data[].attributes.body
In todays lesson, we revised on carbonyl compounds, Aldehyde and Ketone.

Preparation of Aldehyde (CHO Group):

Primary Alcohol + [O] -> Aldehyde

Aldehyde + [O] -> Carboxylic Acid

Note:

To prevent carboxylic acid from forming, heat them gently, add the oxidising agent drop by drop and distill immediately.

Ketone [CO Group]

Secondary Alcohol + [O] -> Ketone

Conditions: Heat under reflux

KMnO4 + heat = purple to colourless

K2Cr2O7 + heat = Orange to green

We also revised on testing for these carbonyl compounds:

2,4 -DNPH

Positive result for aldehyde/ ketone

Deep orange ppt

Tollens’ Reagent

Positive result for aldehyde only

AgNO3 in excess NH3 Solution

Forms silver ppt

Fehling’s solution

Positive result  for aldehyde only

Cu2+ in excess NH3 solution

Forms red ppt from blue solution

Triiodomethane

Test for CH3-C=O group.

Forms yellow ppt

Nucleophilic addition

Reagent : HCN + CN- catalyst

Product: Hydroxy nitrile

Memorise the mechanism.

HCN is formed from NaCN and H2SO4

Reaction of nitrile

Hydrolysis

Heat under reflux

Reagent: H+

Produces carboxylic acid

Reduction

Na + Ethanol

No specific condition

Produces amine

Needs 4 Hydrogen

Reduction of carbonyl

Either alkaline solution of NaBH4 + warm or LiAlH4 in dry ether, rtp

Aldehyde -> primary alcohol

Ketone -> secondary alcohol

Infrared Spectroscopy

“Ghost with a peace sign” is alcohol

Broad at 3400 sharp at 3000

Broad at 3000 , sharp at 1750 is carboxylic acid

Sharp at 3000 and 1750 is ester

I need to memorize the part on Infrared , the mechanism of nucleophilic addition, the triiodomethane reaction as well as all the reagents and conditions for all the reactions.

# data[].attributes.body
1. how to prepare aldehyde: add oxidising agent drop by drop to primary alcohol while heating it gently and distill over the aldehyde once it forms

2. how to prepare ketone: add oxidising agent to secondary alcohol while heating under reflux

3. oxidising agents: acidified KMnO4 (purple to colourless) and acidified K2Cr2O7 (orange to green)

4. reduction of aldehyde: add LiAlH4 in dry ether at room temperature or use warm aqueous alkaline NaBH4, aldehyde will be reduced to a primary alcohol

5. NaBH4 is a mild reducing agent and cannot be used to directly reduce a carboxylic acid into a primary alcohol

6. reduction of ketone: add either warm aqueous alkaline NaBH4 or LiAlH4 in dry ether at room temperature, ketone will be reduced to a secondary alcohol

7. HCN for nucleophilic addition of HCN is prepared in situ, NaCN reacts with dilute H2SO4 to produce NaHSO4 and HCN

8. nucleophilic addition of HCN can occur with both aldehyde and ketone, and the product is always 2-hydroxy...nitrile

9. the nucleophile added is the CN- ions

10. nitrile can be reduced with ethanolic sodium to form an amine

11. 2,4-DNPH (no need for heating): deep orange ppt with carbonyl compound

12. Tollen's reagent (AgNO3 in excess NH3) (mild oxidising agent): forms a silvery mirror when warmed with an aldehyde

13. Fehling's solution (mild oxidising agent) (alkaline solution containing copper (II) ions): turns from clear blue solution into a red/orange/brick red ppt when warmed with an aldehyde

14. Triiodomethane reaction (alkaline solution of iodine): yellow ppt forms when warmed with anything that has a CH3 group (ethanal, methyl ketone, or any alcohol with a CH3 group)

15. alcohol (cute ghost with peace sign) (3400 O–H, 3000 O–H)

16. carboxylic acid (mountain) (3000 O–H, 1750 C=O)

17. ester (icicle) (3000 C–H,1750 C=O)

I need to review more on the reaction of carbonyl compounds, the reaction to form amine and the triiodomethane reaction.

Lesson today was really clear and it was nice to see the cute alcohol ghost again 👻

# data[].attributes.body
1. how to prepare aldehyde: add oxidising agent drop by drop to primary alcohol while heating it gently and distill over the aldehyde once it forms

2. how to prepare ketone: add oxidising agent to secondary alcohol while heating under reflux

3. oxidising agents: acidified KMnO4 (purple to colourless) and acidified K2Cr2O7 (orange to green)

4. reduction of aldehyde: add LiAlH4 in dry ether at room temperature or use warm aqueous alkaline NaBH4, aldehyde will be reduced to a primary alcohol

5. NaBH4 is a mild reducing agent and cannot be used to directly reduce a carboxylic acid into a primary alcohol

6. reduction of ketone: add either warm aqueous alkaline NaBH4 or LiAlH4 in dry ether at room temperature, ketone will be reduced to a secondary alcohol

7. HCN for nucleophilic addition of HCN is prepared in situ, NaCN reacts with dilute H2SO4 to produce NaHSO4 and HCN

8. nucleophilic addition of HCN can occur with both aldehyde and ketone, and the product is always 2-hydroxy...nitrile

9. the nucleophile added is the CN- ions

10. nitrile can be reduced with ethanolic sodium to form an amine

11. 2,4-DNPH (no need for heating): deep orange ppt with carbonyl compound

12. Tollen's reagent (AgNO3 in excess NH3) (mild oxidising agent): forms a silvery mirror when warmed with an aldehyde

13. Fehling's solution (mild oxidising agent) (alkaline solution containing copper (II) ions): turns from clear blue solution into a red/orange/brick red ppt when warmed with an aldehyde

14. Triiodomethane reaction (alkaline solution of iodine): yellow ppt forms when warmed with anything that has a CH3 group (ethanal, methyl ketone, or any alcohol with a CH3 group)

15. alcohol (cute ghost with peace sign) (3400 O–H, 3000 O–H)

16. carboxylic acid (mountain) (3000 O–H, 1750 C=O)

17. ester (icicle) (3000 C–H,1750 C=O)

# data[].attributes.body
This is the summary of what we revised  from the chapter Carbonyl compunds
For the preparation of aldehydes, oxidizing agent is added drop by drop, and is then distilled off to form aldehyde from primary alcohols.

For the preparation of ketone
Secondary alcohol is heated under reflux to form ketone there is no need to add oxidising agent one drop at a time.

For the reduction of aldehyde, aldehyde is reduced to primary alcohol, while ketone is reduced into secondary alcohol. The reducing agent is NaBH4 or LiAlH4 in dry ether,  LiAlH4 can be used to directly reduce carboxylic acid to primary alcohol.

Nucleophilic addition with HCN
HCN is generated in situ with the reaction NaCN + dilute H2SO4
Reactions of nitriles
1. RCN + dilute HCl under reflux —> RCOOH + NH4
2. RCN +  Na in ethanol (4[H]) —> —CH2NH2

Test for 2,,4 DNPH:
- Used to test if aldehyde or ketone is present. Deep orange precipitate if present. No need to heat.

Test for Tollen's reagant:
Is used to test for aldehyde. AgNO3 in excess NH3 solution, warmed, must be heated . Ag+ reduced to Ag, forming silver mirror.

Test for Fehling's solution:
Is a solution of  solution of copper (II) ions it turns into blue when aldehyde is present must be warmed.

Triiodomethane reaction
Test for CH3CO group. Ketone is added with an alkaline solution of iodine and warmed, where methyl ketone and a yellow precipitate is form, which is the triidomethane.

IR Spectroscopy
- Alcohol (3400-3000)
Ghost with peace sign
- Carboxylic Acid (3000-1750)
Broad at  3000 sharp at 17500
- Ester (3000-1750)
sharp at both 3000 and 1750

Need to memorize the solutions and the reactions more.

The lesson was a revision of the carbonyl group helped me clear up things i did not fully understand before.

# data[].attributes.body
- Carbonyl compounds are Aldehyde & Ketone

- For oxidation :
• Primary alcohol --> Aldehyde --> Carboxylic acid
• Secondary alcohol --> Ketone
• Tertiary alcohol --> No reaction

- Preparation of aldehyde :
• Use oxidizing agent
• Heated gently
• Add oxidizing agent drop by drop
• Distillation

- Preparation of ketone :
• Use oxidizing agent
• Heat under reflux

- Reduction :
• Opposite of oxidation
• Reducing agent is aqueous warmed NaBr4 OR LiAlH4 in dry ether at room temperature

- Nucleophilic Addition with HCN
• In situ
• NaCN + dilute sulfuric acid
• Curly arrow diagram

- 2,4 - DNPH
• Use 2.4- dinitrophenylhydrazine
• Turns to deep orange precipitate if Aldehyde/Ketone present
• Recrystallization to identify the ppt

- Tollens' Reagent
• Use AgNO3
• Excess ammonia
• Oxidizing agent is silver ion
• Carboxylate ion formed under alkaline solution
• Silver mirror inside the test tube if Aldehyde present
• If Ketone present, colorless

- Fehling's Solution
• Alkaline solution
• Has copper (II) ions
• Warmed with aldehyde for oxidation to Carboxylate ion
• Red-orange ppt if Aldehyde present
• Remains blue if Ketone present

- Triiodomethane Reaction
• Alkaline solution of iodine
• Warmed
• Yellow ppt
• Test for CH3CO & CH3CH(OH) group

- Infrared Spectroscopy
• Alcohol : Alcohol ghost
• Carboxylic acid : Whale
• Ester : Vampire teeth

# data[].attributes.body
testing for carbonyl compounds :

2.4-DNPH

-deep orange precipitate when in contact with aldehydes or ketones

tollens reagent

-will form silver mirror when heated with aldehyde.

-agno3 in excess nh3.

-ag+ is a mild oxidising agent, it reduced to ag atoms

fehling solution

-alkaline cu2+ ions

-colour change from blue to red/orange when warmed with aldehydes

nucleophilic addition with hcn

-kcn reacts with halogenoalkane

-hcn reacts with ketone

reactions to form tri-iodomethane

-yellow ppt

-carbonyl compounds js halogenated then hydrolysed

-alkaline solution of iodine is used to halogenate the carbonyl compound

-the reaction is used to test for presence of ch3co- group.

primary alcohol- aldehyde -> carboxylic acid

secondary alcohol- ketone

tertiary alcohol -❌

i need to learn more about the mechanism of reaction because i am not so fluent in that part.

the class was overall good as usual, mr gopi discussed the materials before going through some past paper questions and then gave us quizziz after school. he also recorded the lesson which made us easier to revise anytime we want.

# data[].attributes.body
In today's chemistry class, we learnt about Carbonyl Compounds like Aldehydes and Ketones. It was indeed a fruitful discussion and here are the things that Mr Gopi had discussed:

Aldehyde (CHO functional group)

Formation of Aldehyde:
- Oxidation of Primary Alcohol
- To prevent further oxidizing to Carboxylic Acid, the oxidizing agent is added drop by drop while being heated gently and is distilled off immediately.
- Primary Alcohol  —> Aldehyde
CH3CH2OH + [O] —> CH3CHO + H2O
- Primary Alcohol  —>  Carboxylic Acid
CH3CH2OH + 2[O] —> CH3COOH + H2O

Ketone (CO functional group)

Formation of Aldehyde:
- Oxidation of Secondary Alcohol
- Heated under reflux, and it is not required to add the oxidizing agent drop by drop.
-  Secondary Alcohol  —>  Ketone
CH3CH(OH)CH2CH3 + [O] —> CH3COCH2CH3 + H2O

Reduction of Aldehyde and Ketone
Aldehyde —> Primary Alcohol

Ketone —> Secondary Alcohol
Reduced by:

NaBH4 (warmed aqueous alkaline)

LiAlH4 (in dry ether, room temperature) [this reducing agent is used when reducing carboxylic acid to primary alcohol]

Nucleophilic Addition with HCN

HCN prepared in situ

NaCN + dilute H2SO4 —> NaHSO4 + HCN

Aldehyde + HCN  —>  hydroxy nitrile
CH3CH2CHO + HCN  —>  CH3CH2CH(OH)CN

Reaction of Nitriles

RCN + dilute HCl under reflux —> RCOOH + NH4+

RCN +  Na in ethanol (4[H]) —> —CH2NH2

Testing For Aldehydes and Ketones

2,4-DNPH
- Test for aldehyde/ketone
- Deep orange ppt. with ketone or aldehyde
- Can be purified & crystalised & used to identify the carbonyl compounds used.

Tollens’ Reagent
- Test for aldehyde.
- Mild oxidizing agent
- AgNO3 in excess NH3 solution
- When warned with aldehyde, it forms a silver mirror

Fehling’s Solution
- Test for aldehyde
- Mild oxidizing agent
- Alkaline solution that contains Cu2+ (blue clear solution) that when warmed with aldehyde, reduces to Cu+ and red ppt will be formed

Triiodomethane
- Test for anything that has a CH3 group
- Alkaline solution of iodine that when warmed, a yellow ppt will be formed

Infrared Spectroscopy

Alcohol (broad at 3400, sharp at 3000) (cute ghost with a peace sign)

Carboxylic Acid (very broad at 3000, sharp at 1750) (whale/mountain)

Ester (sharp at 3000 and 1750) (icicles/vampire fangs)

Comments!
I feel like I need to focus more on the test for Aldehydes and Ketones as memorizing it can be quite challenging sometimes.

But other than that, Mr Gopi has cleared all other doubts on this chapter when explaining today. It was yet another useful lesson and I'm glad to have him as my chemistry teacher :D Lastly, as the prelims are like in 10 days, I feel like Mr. Gopi has done an amazing job at covering the topics for Organic Chemistry especially since we're having a race against time!

# data[].attributes.body
I was able to revise about the conditions for the oxidation and reduction of aldehyde and ketone, the tests for it and how to determine the infra-red spectrum of alcohol, carboxylic acid and ester. I learned how to properly write the mechanism of nucleophilic addition of HCN.

# data[].attributes.body
• Preparation of aldehyde
- primary alcohol —> aldehyde —> carboxylic acid
To prevent carboxylic acid from forming:
- heat them gently
- add the oxidising agent one drop at a time
- distill immediately
KMnO4 purple to colourless
K2Cr2O7 orange to green

• Preparation of ketone
- secondary alcohol —> ketone
- heated under reflux
- no need to add oxidising agent one drop at a time

• Reduction of aldehyde and ketone
- Aldehyde is reduced to primary alcohol
- Ketone is reduced to secondary alcohol
- Reducing agent: NaBH4 (aq alkaline, warmed OR LiAlH4 in dry ether, rt)
- LiAlH4 can be used to directly reduce carboxylic acid to primary alcohol

• Nucleophilic addition with HCN
- HCN is prepared in situ
NaCN + dilute H2SO4 —> NaHSO4 + HCN
Reaction of nitriles
1. RCN + dilute HCl under reflux —> RCOOH + NH4+
2. RCN +  Na in ethanol (4[H]) —> —CH2NH2

• Testing for aldehydes and ketones

1. Test with 2,4-DNPH
- Dont need to heat
- Deep orange ppt if aldehyde or ketone is present

2. Tollens' Reagent
- Silver mirror
- Must be warmed
- AgNO3 in excess NH3 solution
- Used to test for aldehyde
- Oxidising agent and it will get reduced

3. Fehling's Solution
- Brick red ppt
- Must be warmed
- Used to oxidise aldehyde only
- Oxidising agent and it will get reduced

4. Triiodomethane Reaction
- Test for CH3CO group
- Positive reaction: ethanal, methyl ketones, some alcohols with CH3CO structure
- Yellow ppt

• IR Spectroscopy
- Ghost = alcohol (3400, 3000)
- Fangs = ester (3000, 1750)
- Whale = carboxylic acid (3000, 1750)

I need to learn more about drawing the structure of 2,4-DNPH

Teaching was helpful and detailed.

# data[].attributes.body
I am able to revise the conditions for the reactions of carbonyl compounds, reactions of nitriles and the mechanism of 2,4-DNPH, as well as the results of Fehling's solution, Tollen's reagent and Tri-iodomethane

# data[].attributes.body
I learned that aldehydes are prepared by dropping an oxidising agent (K2Cr2O7 / KMnO4) one drop at a time to heated primary alcohol or it will turn to carboxylic acid instead. Ketones, however, are made from oxidising secondary alcohol heated under reflux and the oxidising agent can be added all at once.

Aldehyde and ketones can be reduced to primary and secondary alcohol respectively using NaBH4 in a warm and alkaline condition while LiAlH4 is used to reduce carboxylic acid to a primary alcohol.

Nucleophilic addition occurs when aldehyde is mixed with hydrocyanic acid (prepared in situ with NaCN and dilute H2SO4) to create a hydroxynitrile that can be reduced to an amine using sodium and ethanol.

The presence of aldehyde and ketone will be tested using 2,4-DNPH (without heating) and deep orange ppt will be seen. Aldehydes are tested using Tollen's reagent (AgNO3 in excess NH3) to see a silver mirror ppt and using Fehling's solution (alkaline solution with Cu2+ ions) to see a brick red ppt forming from a clear blue one. Triiodomethane reaction is used to test for CH3CO and CH3CH(OH) groups and it will form a yellow ppt.

For the IR spectroscopy,

- alcohol (broad at 3400, sharp at 3000)

- carboxylic acid (very broad at 3000, sharp at 1750)

- ester (sharp at 3000 and 1750)

I need to practice drawing the 2,4-DNPH and the mechanism of nucleophilic addition more.

# data[].attributes.body
I learnt that Prep of aldehyde and ketone are heated under reflux.

Creation of aldehyde uses primary alcohol and oxidising agent drop by drop and imediatelly distilled or it will become carboxylic acid.

Creation of Ketone uses secondary alcohol heated under reflux without drop by drop.

Aldehyde and Ketone can be reduced to primary and secondary alcohol respectively using warmed NaBH4 or room temp LiAlH4 in dry ether

HCN is prepared in situ using dil H2SO4 and NaCN and can be reduced using sodium in ethanol.

2,4 dnph will turn deep orange in pressence of aldehyde or ketone and no warming is needed

Felings solution(AgNO3 + NH3) in pressence of aldehyde will turn blue to  brick red

Tollen reagent will form silver ppt in pressence of aldehyde

Triiodomethane- test carbonyl compound.alcohol with CH3(methane) and ethanal. froms yellow ppt

Alcohol is ghost with peace sign(3400 and 3300)
Carboxylic acid is whale(3000 1750)
Ester is fangs(3000 1750)

# data[].attributes.body
I learnt about aldehyde and ketone and carboxylic acid production and how to reduce them as well. Something new would be

Fehling- aldehyde, blue to brick red
Tollen- alderhyde, silver ppt formed
2,4 DNPH- both aldehyde and ketone, no need to be warmed, orange ppt formed
Triiodomethane- methyl ketone group, ethanol and ethanal.

IR spectroscopy

Alcohol, 3400 3000
Carb acid, broad 3000 1750
Ester, narrow 3000 1750

# data[].attributes.body
We revised the methods of preparing and reducing aldehydes. To prepare aldehydes, a primary alcohol is reacted with an oxidation agent (acidified KMnO4 (VII) or acidified K2Cr2O7 (VI)); it must be heated under reflux gently and the oxidation agent must be added drop by drop. When the aldehyde forms, it must be distilled immediately. To reduce an aldehyde, it must be reacted with a reduction agent (LiAlH4 in dry ether, which has higher reactivity, or NaBH4).

We also revised the methods of preparing and reducing ketones. To prepare ketones, a secondary is reacted with an oxidation agent and heated under reflux. Unlike preparing aldehydes, since there will be no further reactions after the ketone is formed, there is no need to heat the reactants gently nor to distill the product immediately after formation. To reduce a ketone to a secondary alcohol, it must also be reacted with a reducing agent.

We also revised carbonyl reactions: to prepare for HCN for its nucleophilic addition with a carbonyl compound, NaCN and H2SO4 are heated in situ. The C=O bond in the carbonyl compound is turned into HO≡CN. Nucleophilic addition involves heterolytic fission; C atoms will have a delta positive charge while O atoms will have a delta negative charge.

We also revised tests for aldehydes; 2,4-DNPH (dinitrophenylhydrazine; can also be used to test for ketones), Tollen's reagent, Fehling's reagent and tri-iodomethane can be used.

A positive result using 2,4-DNPH is shown by the formation of an orange precipitate, which can be purified and crystallised, then used to identify the ketone or aldehyde formed. Due to the reactivity of 2,4-DNPH, heating the reactants is unnecessary.

A positive result using Tollen's reagent is shown by the formation of a silver mirror. Tollen's reagent consists of AgNO3 in a solution of excess NH3; the Ag+ ion acts as an oxidising agent, oxidising the aldehyde into a carboxylic acid. The Ag+ ions are reduced to Ag atoms, forming a "silver mirror". Heating the reactants is necessary.

A positive result using Fehling's reagent is shown by the formation of a red precipitate. Fehling's reagent consists of Cu2+ ions, which is reduced by the aldehyde into Cu atoms, forming a red precipitate.

A positive result using tri-iodomethane is shown by the formation of a yellow precipitate. This only works with the aldehyde ethanal -  tri-iodomethane tests for the CH3CHO group; if it is present, the alkaline solution of iodine forms a (crystallised) yellow precipitate. Heating is necessary.

We also revised infrared spectroscopy; we were advised to ignore values of 800-1400. Alcohol graphs have a distorted blob-like shape, or a "ghost holding up a peace sign" when rotated. It has peak points at 3400 and 3000. Carboxylic acid graphs take on the shape of a mountain, with a broad area at 3000 and a sharp peak at 1750. Ester graphs have a form reminiscent of icicles in a cave, with two sharp edges at 3000 and 1750 respectively.

♥︎

To revise: I still have trouble with everything shown in the form of any type of formulae.

♥︎

The class was simple and straightforward; it helped me understand things I found difficult when reading the textbook. I also really like it that we take a quizizz after every class. Although I find the time count intimidating, the quiz itself helps me recall what I learned and reminds me of points I would otherwise have missed.

# data[].attributes.body
I tried copying down as much as I could given that my phone wasn't being co-operative ://

I learned that the nucleophilic addition of HCN includes both aldehydes and ketones through asking questions :0

*Carbonyl Compounds*

1. Aldehydes
2. Ketones

*Aldehydes*
- CHO functional group

*_preparation of aldehyde_*

- primary alcohol + Oxidising agent, heated under reflux gently, added one drop at a time = aldehyde (distilled off as it is formed

*Note : oxidisation agent = KMnO4 or K2Cr2O7

- ethanol + Oxidising agent = ethanal
- CH3CH2OH + [O] = CH3CHO + H2O

- ethanol + Oxidising agent = Carboxylic acid
- CH3CH2OH + 2[O] = CH3COOH + H2O

*_reduction of aldehydes_*

- reducing agents = LiAlH4 in dry ether > NaBH4

- aldehyde + reducing agent = Primary Alcohol
- CH3CHO + 2[H] = CH3CH2OH???

*Ketone*
- CCOC functional group

*_preparation of ketone_*
- secondary alcohol + oxidising agent, heated under reflux = ketone
- propan-2-ol + Oxidising agent = propanone
- CH3CH(OH)CH3 + [O] = CH3COCH3 + H2O

*_reduction of ketones_*

- ketone + reducing agent = Secondary Alcohol
- CH3COCH3 + 2[H] = CH3CH(OH)CH3

*Reactions of Aldehydes and Ketones*

1. Nucleophilic Addition with HCN

* Note : HCN generated in situ
- NaCN + dilute H2SO4 = NaHSO4 + HCN

- Aldehyde + HCN = hydroxy nitrile
- CH3CH2CHO + HCN = CH3CH2CH(OH)CN

*Hydrolysis*
-

*Reduction*
-

*Mechanism*

*Testing for Aldehydes and Ketones*

1. 2,4- Dinitrophenylhydrazine
2. Tollen's reagent
3. Fehling's reagent
4. Triodomethane reaction

*_2,4-DNPH_*
- Deep orange ppt with ketone/aldehyde
- ppt can be purified + crystalised & used to identify ketone/aldehy used

*_Tollen's reagent_*
- AgNO3 in excess NH3 solution
- silver ion acts as oxidising agent
- aldehyde oxidised into carboxylic acid
- silver ions for silver atoms, forms silver mirror
- Positive test for aldehyde = silver mirror

*_Fehling's reagent_*

*_Triiodomethane reaction_*
- Test for CH3CO/CH3COH group
- Ethanal/Methyl Ketones
- Alkaline solution of Iodine, heated
- Forms yellow ppt

*Infrared Spectroscopy*

1. Alcohol
2. Ester
3. Carboxylic acid

*_Alcohol_*
- Scoliosis whale / ghost
- 3400 3000
- broad sharp

*_Carboxylic acid_*
-
- 3000 1750
- broad sharp

*_ester_*
- vampire teeth
- 3000 1750
- sharp sharp

# data[].attributes.body
I learnt that the drop by drop addition of oxidising agent is only needed for the formation of aldehydes and not ketones. I also learnt that when writing the compound we do HO instead of OH as the latter is referring to alcohols. I also learnt that the triiodomethane reaction return a positive result only in the presence of a CH3CO group.

# data[].attributes.body
I learnt that the preparation of aldehyde and ketones have to be heated under reflux

- Primary alcohols are oxidized to become aldehyde and are further oxidized to become carboxylic acid

- Secondary alcohols are oxidized to become ketones

- Tertiary alcohols cannot be oxidized

- To prepare aldehyde, the alcohols have to be heated gently and oxidizing agent is added drop by drop and distilled off, so that it does not directly become carboxylic acid

- Reduction agent for Aldehyde and Ketone is warmed NaBH4 or LiAlH4 in dry ether
C acid ->              Aldehyde      ->      Primary
NaBH4                     LiAlH4 / NaBH4

- Nucleophilic Addition with HCN requires HCN + dilute H2SO4

- 2,4 DNPH solution turns to deep orange ppt if aldehyde or ketone is present

- Tollen's Reagent turns to a silver ppt if aldehyde is present

- Fehling's solution turns red/orange when aldehyde is present and remains blue when ketone is present

- IR spectroscopy of ester and c acid highest points 3000, 1750
ester pointy, c acid curvy

-IR spectroscopy of alcohol highest points 3400, 3000

# data[].attributes.body
I learnt that
- dropping oxidising agent drop by drop is not needed for the oxidation of secondary alcohol
- HCN prepared in situ (same reacting vessel) :  dilute H2SO4 + NaCN
- tests for aldehyde : 1. tollen’s reagent positive test forms silver mirror ppt, 2. fehling’s reagent positive test forms brick red ppt, both must be warmed.
- iodoform test : test for ketone (ethanal) and secondary alcohol attached to methyl group, yellow ppt formed for positive test and it’s mechanism
- NaBH4 cannot reduce carboxylic acid, LiAlH4 can
- NaBH4 and LiAlH4 used as reducing agents
-IR spectroscopy :
vampire fangs/ icicle/ sharp drops : ester
curve / upside down ghost : alcohol
Broad with sharp peak : carboxylic acid

# data[].attributes.body
CARBONYL COMPOUNDS

a) Aldehyde

b) Ketone

ALDEHYDE

1. Oxidising agent is added drop by drop while being heated gently.

2. Distilled off immediately.

KETONE

1. Add oxidising agent drop by drop and heated under reflux.

OXIDATION OF 1° and 2º ALCOHOLS

1. Aldehyde:

CH3CH2OH + 2[O] —> CH3COOH + H2O

1. Ketone:

CH3CH(OH)CH2CH3 + [O] —> CH3COCH2CH3 + H2O

REDUCTION OF ALDEHYDE AND KETONE

Aldehyde —> Primary Alcohol

Ketone —> Secondary Alcohol

Reduced by: NaBH4 (warmed aq alkaline), LiAlH4 (in dry ether, rtp)

NUCLEOPHILIC ADDITION

1. In situ with NaCN + H2SO4 —> NaHSO4 + HCN

2. C=O transformed to HO-C(triple bond)CN

HYDROLYSIS TO FORM RCOOH

1. Dilute HCl

RCN + H+ + H2O —> RCOOH + NH4+

1. Ethanolic Na

RCN + 4[H] —> RCH2NH2

CHEMICAL TESTS

1. 2,4-DNPH: Test for carbonyl compounds. “-zine” to “-zone” causes formation of deep orange ppt.

2. Tollens’ Reagent: Test for aldehyde. AgNO3 in excess NH3 solution, warmed in water bath. Ag+ reduced to Ag, forming silver mirror.

3. Fehling’s Solution: Test for aldehyde. Alkaline Cu2+ warmed, reduced to Cu+ and red ppt will be formed.

4. Triiodomethane: Test for CH3CO and CH3CH(OH) groups. Alkaline solution of iodine is warmed, forming yellow crystals.

INFRARED SPECTROSCOPY

1. Ester: Vampire teeth, s at 3000 and s at 1750

2. Carboxylic acid: Camel, broad s at 3100 and s at 1750

3. Alcohol: Alcohol ghost or scoliosis whale, s at 3000 and 3350

WHAT I NEED TO LEARN MORE
Remembering the wave absorption and the constituents of the chemical test reagents.

TEACHING
Teaching was elaborate and concise.

# data[].attributes.body
Things I learned is that NaBH4 in alkaline solution cannot be reduced to primary alcohol due to its acidic nature. Preparing aldehyde should also be distilled immediately and and acidified KMnO4 should be added drop by drop and for preparing carboxylic acid, distillation is not required and acidified KMnO4 doesnt need to be added drop by drop. Sodium in ethanolic conditions can reduce nitriles to amine.Tollen's reagent consists of ammonia soultion and silver nitrate while Fehlings's solution consists of copper(ii) nitrate and NaOH solution

# data[].attributes.body
We learnt about the properties and reactions of carbonyls, including how to make them with oxidizing agents, how to reduce them, the tests to identify them and so on.

We also learnt about the IR spectroscopy and the different identifiers for the different types of compounds.

# data[].attributes.body
Learnt:

preparation of ketone don’t need to add oxidizing agent drop by drop.

Reducing agent: LiBH4 in dry ether or warmed NaBH4 in aq, alkaline.

NaBH4 is not suitable to reduce c.acid into primary alcohol.

Nucleophilic addition (HCN produced in situ -> NaCN + dil H2SO4)

Test with 2,4 - DNPH (deep orange ppt) positive for aldehyde and ketone

Tollens’ Reagent (silver atoms/mirror appearance) and Fehling’s Solution (clear blue solution turns red/orange) positive for aldehyde (both needs to be warmed)

Triiodomethane reaction test for CH3CO group (forms yellow ppt)

IR spectroscopy for c.acid, ester and alcohol

I need to review more on how to draw triiodomethane and the curly arrow diagrams for nucleophilic addition reaction.

Teaching was clear.

# data[].attributes.body
Preperation of Aldehyde
-Oxidising agent is added one drop at a time
-Distilled off as it formed
-Priamry Alcohols

Preperation of Ketone
-heated under reflux
-No need to drip oxidising agent
-Secondary Alcohol
-H is taken away from the OH

Reduction of Aldehyde
-Aldehyde reduced to primary alcohol
-Ketone reducded to secondary alcohol
-Reducing agent: NaBH4(aq, alkaline, warmed or LiAlH4 in dry ether, rt)

Nucleophilic addition with HCN
-HCN generated in situ
-NacN  + dil H2SO4

*Hydrolysis can eb carried out by refluxing with dilute hydrochloric acid
*Reduction of nitril group to an amine can be carried out using sodium and ethanol

Mechanism
1. Double bound with O is gone and O becomes a nucleophile CN is added to the CN, this makes it an intermediate
2. The O ion is bonded with O Electrophilic H  and becomes OH.

Test for 2,4 DNPH
-Deep orange precipitate if aldehyde or ketone is present
-No heating needed

Tollen's Reagant
-AgNO3 in excess NH3 solution called as ammonical silver nitrate solution
-Must be watm
-Silver ions act asa mild oxidising agent
*Only for aldehyde
-Silver ions from silver atoms
-silver mirror ppt

Fehling's solution
-Alkaline solution containing copper(ii) ions
-needs to be watmed with aldehyde

Triiodomethane reaction
-Test for CH3CO group
-Alkaline solution with iodine and warmed
-Ethanol (the only aldehyde)
-ppt is yellow crystalline
-Brick red ppt

Spectroscopy
-Ignore 800-1400

-3400 & 3000
Ghost with peace sign
Alcohol

-3000 & 1750 (sharp peaks)
Ester

3000 & 1750 (broad with sharp peak)
C.Acid

The lesson was a fresh revision of the carbonyl group. I learnt alot more about the things used to test the carbonyls and how they work. I now know alot more of the carbonyl group in detail, how they react and what conditions are needed. I also learnt again about the spectroscopy diagrams.

# data[].attributes.body
We revised about Aldehydes and Ketones.
Preparation of Aldehyde
- Primary Alcohol
- Oxidizing Agent which is added one drop at a time
- Heated under Reflux
- Distilled as it is formed

Reduction of Aldehydes and Ketones
- Aldehydes are reduced to primary alcohols while Ketones are reduced to secondary alcohols.
- Reducing Agnet can be NaBH4, a warmed aq alkaline or LiAlH4 in dry ether with room temperature.

Nucleophilic Addition with HCN
- HCN is generated in situ
- NaCN + dil H2SO4

A test with 2, 4-DNPH can be used to see if an aldehyde or ketone is present. An orange precipitate would be formed.

Tollen's Reagant is AgNO3 in excess NH3 solution. If an aldehyde is present silver ions would be formed. The solution would remain colorless if tested with Ketones.

Fehling's solution is an alkaline solution containing copper (II) ions. It would turn from a clear blue into a red/orange color if an aldehyde is present. If a ketone is tested with this, the solution will stay blue.

Triiodomethane reaction is used to test for the CH3CO group.  If the CH3CO group is present, a yellow precipitate would be formed in the form of crystals.

Infrared Spectroscopy
- Alcohol (3400-3000)
Ghost with peace sign
- Carboxylic Acid (3000-1750)
- Ester (3000-1750)

The lesson today was easy to follow and clear as usual. I need to further revise on all the different tests for aldehydes and ketones.

# data[].attributes.body
I learned about the oxidation of primary alcohol into aldehyde and further oxidize into carboxylic acid and the oxidation of secondary alcohol into ketone. I also learned about the testing for carbonyl compounds.

Preparation of aldehyde:
-Oxidizing agent is added drop by drop, where later it is distilled off to form primary alcohol.

Preparation of ketone:
- Secondary alcohol is heated under reflux

Reduction of aldehyde:
- Aldehyde is reduced to primary alcohol, while ketone is reduced into secondary alcohol. The reducing agent is NaBH4 or LiAlH4 in dry ether.

Nucleophilic addition with HCN
- HCN is generated in situ with the reaction NaCN + dilute H2SO4

Test for 2,,4 DNPH:
-Deep orange precipitate if aldehyde or ketone is present

Test for Tollen's reagant:
-Silver mirror precipitate is form when there is aldehyde present. The silver mirror is form from silver ions from AgNO3.

Test for Fehling's solution:
-it turns into blue when aldehyde is present

Triiodomethane reaction
- Test for CH3CO group
- Ketone is added with an alkaline solution of iodine and warmed, where methyl ketone and a yellow precipitate is form, which is the triidomethane.

IR Spectroscopy
- Alcohol (3400-3000)[Ghost with peace sign]
- Carboxylic Acid (3000-1750)
- Ester (3000-1750)
- Ignore 800-1400

I need to revise more on the positive test of aldehyde and ketone with different solutions.

# data[].attributes.body
Two oxidizing agents KMnO4 purple - colourless K2CrO7 orange - green. Aldehyde is formed when primary alcohol is oxidized. Preparation of ketone: heated under reflux and no need to use oxidising agent. 2,4 NPH can be used for ketone and aldehyde, deep orange precipitate is formed if aldehyde and ketone is present. Tollens reagant is only for aldehyde, silver ions form when aldehyde present. Fehlings solution turns orange when aldehyde is present, remains blue when ketone is present. Triiodomethane reaction is used for testing CH3CO Group. It forms yellow crystalline.

# data[].attributes.body
We revised about the Carbonyl compounds that includes Ketones and Aldehydes. We also learned about their reaction, ex: Nucleophilic additions with HCN, oxidation, etc. We also learned on how to test them: 2,4 DNPH is to test for both, while Tollens' and Fehling's is used to test for aldehydes only. Lastly we also learned about the spectrum. With each compound having their own unique peak values.

# data[].attributes.body
Reviewed on :
- primary alcohol -> aldehyde -> carboxylic acid ( oxidation )
- secondary alcohol -> ketone ( oxidation )
- tertiary alcohol ( cannot be oxidised )
- oxidising agents — KMnO4 ( purple to colorless) , K2Cr2O7 ( orange to green )
- reducing agents : LiAlH4 in dry ether and NaBH4 in aqueous, alkaline
- nucleophilic addition using HCN -> NaCN + dilute H2SO4 in situ
- curly arrow diagram for nucleophilic addition
- 2,4 DNPH -> positive -> ketone&aldehyde
- warmed Tollen’s reagent ( AgNO3 in excess NH3 ) -> positive for aldehyde only
- fehling’s solution -> Cu2+ ions -> positive for aldehydes only
- tri-iodomethane reaction -> methyl ketones, ethanal -> positive -> yellow crystals
- IR spectroscopy : esters, C.acids, Alcohols

I need to practice on the IR spectroscopy absorbances, and also the tests for carbonyl compounds

Teaching was detailed, very good revision

# data[].attributes.body
Preparation of carbonyl compounds, reduction of carbonyl to form alcohol, nucleophillic addition, testing for carbonyls with DNPH and oxidation. IR spectometry 3400, 3000, 1750. Mountain-carboxylic acid, cat-ester, ghost-alcohol. Iodoform reactions.

# data[].attributes.body
aldehyde (CHO)

ketone (COC)

OXIDATION ( + [O] )

—preparation of aldehyde

1. primary alcohol

2. oxidising agent (added one drop at a time)

3. heated gently (no formation of carboxylic acid)

4. distilled off as it formed

—preparation of ketone

1. secondary alcohol

2. same oxidising agent (no need to add drop by drop)

3. heated under reflux

REDUCTION ( + [H] )

—aldehyde and ketone

1. aldehyde is reduced to primary alcohol

2. ketone is reduced to secondary alcohol

3. reducing agent : NaBH4 (aq alkaline, warmed or LiAlH4 in dry ether, rt)

4. carboxylic acid to primary alcohol (cannot use NaBH4, use LiAlH4)

NUCLEOPHILIC ADDITION WITH HCN

1. generated in situ (NaCN + dil H2SO4 —> NaHSO4 + HCN)

2. RCN (nitrile)

a. RCOOH + NH4+ (dil HCl — hydrolysis)

b. amine (sodium + ethanol)

TESTING ALDEHYDE AND KETONES

1. 2,4 - DNPH (no heat, deep orange ppt if aldehyde or ketone is present, ppt can be purified by recrystallisation and melting point can be found experimentally to identify the ppt)

2. tollen’s reagent (warmed, silver nitrate in excess ammonia solution, silver ion behaves as mild oxidising agent, carboxylate ion is formed under alkaline solution, silver mirror —> aldehyde)

3. fehling’s solution (warmed, alkaline solution of copper (II) ions, aldehyde is oxidises to carboxylate ion and copper (ii) ions reduced to copper (I) oxide, red orang ppt)

4. TRIIODOMETHANE (test for CH3CO, alkaline solution of iodine, warmed, yellow ppt —> ethanal, methyl ketones)

INFRARED SPECTROSCOPY

1. alcohol (3400, 3000, ghost peace sign)

2. carboxylic acid (3000, 1750, broad)

3. ester (3000, 1750, iceberg, sharp)

# data[].attributes.body
Carbonyl compounds , infra-red spectroscopy

Carbonyl compounds : Aldehyde (-CHO) , ketone (R1COR2)

Preparation of aldehyde (oxi primary alcohol)
- Oxi agent : acidified potassiun dichromate (VI)
* added one drop at a time
- Heat gently
- Obeservation :
- Distilled off as it formed so no further oxi occur

1. Heat gently
2. Drop by drop
3. Distill immedietly

Preparation if ketone (oxi secondary alcohol)
- Oxi agent : acidified potassiun dichromate (VI)
- Heated under reflux
- No need to add drop by drop

Reduction of aldehyde and ketone
- Aldehyde -> Primary alAlcohol
- Ketone -> Secondary Alcohol
- Reducing agent
*NaBH4 -> aq alkaline , warmed
1.Mild reducing agent (1 step at a time , c.acid to aldehyde to primary alcohol)
*LiAlH4 -> in dry ether, r.t
1.Strong reducing agent (2 step , c.acid to primary alcohol)

Ex:
CH3CHO + 2[H] --> CH3CH2OH
CH3COCH3 + 2[H] --> CH3CH(OH)CH3

Nucleophilic addition with HCN
- HCN generated in situ
- NaCl + dil H2SO4 -> NaHSO4 + HCN
- Can react with aldehyde and ketone

RCN - nitrile :
1. Dilute HCl , reflux -> RCOOH + NH4+
2. Sodium in ethanol -> NH2 (amine)

Mechanism of Nucleophilic addition :
1. C - delta positive , O - delta negative
2. Heterolytic fission

Testing for aldehyde and ketone
1. Test with 2,4-DNPH
- Aldehyde and ketone : deep orange ppt
- Know how to draw the structure of 2,4-DNPH
- No need to heat
- Ppt can be purified by recrystalisation and melting point can be found experimentally to identify the ppt

2. Tollens' Reagent (must be warm)
- AgNO3 in excess NH3 solution - ammoniacal silver nitrate solution
- Silver ion - mild oxi agent
- carboxate ion is form ( under alkaline solution)
- Positive reaction : Aldehyde
- Silver ions form silver atoms (mirror inside the tube)

3. Fehling solution (must be warm)
- Alkaline solution contain copper(II) ions
- Aldehyde is oxidized to carboxylate ion
- Positive reaction : aldehyde , brick red ppt

Triiodomethane reaction
- Test for CH3CO- group
- Alkaline solution of iodine and warmed
- Positive reaction : Ethanal
- Form yellow ppt / crystals
- NaOH

Infra-red spectroscopy
- Ignore 800- 1400
- 3400 ,  3000 , 1750
- Ghost with peace sign- Alcohol
- Vampire fangs - Ester
- Mountain - C.acid
- Ester : 3000 - 1750
- C.acid : 3000 - 1750
- Alcohol : 3400 - 3000

Need to revise more :
- Know the 3 value for Infra red
- Practice the reactions
- Remember the different tests and conditions

# data[].attributes.body
Today, we learnt all about carbonyl compounds, which are aldehydes and ketones. We learnt about what they are (they have the aldehyde group), how to form them (oxidation, aldehydes can become carboxylic acids unless you distill them immediately), the tests for them ( Fehlings and Tollens, silver and brick red ppt respectively ), and the reactions they have.

I think the ones I definitely need to learn on my own are its reactions to form triiodomethane, nucleophilic substitution and the test with 2,4 dinitrohydrazine.

Triiodomethane:
- Test for CH3CO/CH3COH group
- Ethanal/Methyl Ketones
- Alkaline solution of Iodine, heated
- Forms yellow ppt
- CH3 becomes CI3H, and it is that yellow ppt
- A carboxyl Na salt (???), with the formula of RCOONa+ is formed as well

Nucleophilic Substitution:
- NaCN and diluted H2SO4 needed to form NaCN
- The intermediate formed will be a carbocation, it will have one singular negative charge (the O-) , and the CN will be neutral.
- The product formed can later on be refluxed/ react respectively with dilute HCl and and hydrogen to later form carboxylic acid and amine groups.

2,4 dinitrohydrazine:
- I just need to remember its structure
- orange ppt formed for aldehydes and ketones
- does not react with ester or carboxylic acids !!