Reflection on lecture 5 : ALCOHOL,ESTER AND CARBOXYLIC ACID by Pooganeswari Siteram Pillai https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav Please write what you have learnt about today, what you need to revise more and comment on my teaching. en-us 2021-08-09 06:25:54 UTC 2026-03-07 00:43:15 UTC hello@padlet.com Elizabeth Donna - Jc2T https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672614073 Alcohol , Ester , Carb.acid 

ALCOHOL :
 - CnH2n+1OH
 - Primary -OH (1R)
 - Secondary -OH (2R)
 - Tertiary -OH (3R) 

Reactions with alcohol :
 - Combustion (complete) 
 1. C3H7OH + 9/2O2 --> 3CO2 + 4H2O
 *Product : CO2 + H2O
 *Balance eq. 

-Nucleophilic substitution  
 *Halogenalkane 
 1. Elimination : NAOH(aq), AgNO3(aq), NaOH(ethanol) 
 2. KCN
 3. Excess NH3 ethanolic 
 * Product : halogenoalkane + water 
 * Heat under reflux 
 *HCl --> prepared in situ (same reaction vessel) [use conc. H2SO4]
 *SOCl2 (Heat under reflux) 
 ^Advantage : Gas will be release , no need to distill / no need to separate 
 *PCl5 (R.T)
 ^Release white steamy fumes -Test for hydroxyl group 
 ^Do not require heating PCl5 - PCl3 (need heating) 
 *PI3 - In situ , heat P & I2 , heat under reflux
 *PBr3 - In situ , heat under reflux 

(Nacl +H2SO4 --> NaHSO4 + HCl) 
 *alcohol more volatile than halogenoalkane 

- Reaction with Sodium Metal 
 1. No reaction with sodium hydroxide 
 2. Product : Salt + Hydrogen (g) 
 3. Sodiun ethoxide salt : white crystalline solid
 4. Less reactive - longer carbon chain , non polar, difficult for oxygen and hydrogen to break 

- Esterification 
 1. Between alcohol & Carboxylic acids 
 2. Catalyst : Conc. H2SO4 
 3. Heat under reflux
 4. Ester - Sweet , fruity smell 
 5. Product : ester +water
 6. Name : Alcohol (-yl)(1st) , Carb.acid (-oate) (2nd)
 7. Hydrogen come from alcohol and OH come from carb. acid 
 8. Work backwards (from ester) : Separate double bond O 

- Reaction with alcohol : 
 Dehydration
 1. Removal of water molecule from alcohol 
 2. Catalyst : Hot Aluminium oxide , Al2O3 , Conc. H2SO4/H3PO4
 3. Heat under reflux
 4. Product : Ethene +water 

- Oxidation 
 1. Primary alcohol -> Aldehyde -> Carboxylic acid 
 2. Secondary alcohol -> Ketone 
 3. Tertiary alcohol -> cannot oxidize 
 4. OXI AGENT : 
 * KMnO4 (VII)  - Purple (MnO4-) to colourless (Mn2+)
 * K2Cr2O4 acidfied (VI) - Orange(Cr2O7 2-) to green (Cr3+) 

- Ester 
 1. Hydrolysis
 2. Heat under reflux with acid or base 
 3. Acid - reversible , product : C.acid + alcohol 
 4. Base - irreversible , +NaOH, product : salt + alcohol 

RCOOH + NaOH
 RCOO-Na+ + NaOH 

- Carboxylic acids 
 1. Formed from nitriles 
 2. Reflux with dilute HCl (need water - hydrolysis) 
 3. Reaction :
 * Weak acids
 * With alkalis - salt + H2O
 * with reactive metals - Salt + H2(g) 
 * with carbonates - Salt + H2O + CO2
 * Reduction using Lithium tetrahydridoaluminate , LiAlH4 , in dry ether (vigorous with water) at room temperature 

Need to practice more :
 1. Conditions
 2. Carb.acid conditions
 3. Oxi's reaction ]]> 2021-08-09 07:29:26 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672614073 sharon jc2truth https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672621657 alcohol
— complete combustion (product carbon dioxide and water)
— nucleophilic substitution with hydrogen halide (in situ; same reaction vessel;)
— nucleophilic substitution with SOCl2 (benefit: since two of the products are gas, it is easier to collect the halogenoalkane)
— nucleophilic substitution with PCl5 (room temperature, release steamy fumes : test for hydroxyl group/alcohol, product : halogenoalkane, HCl, POCl3)
— nucleophilic substitution with PCl3 (heat under reflux)
— nucleophilic substitution with PI3 or PBr3 (heat under reflux, in situ using red phosphorus and bromine/iodine, product H3PO3)
— sodium metal (forming alkoxide salts and hydrogen gas, longer the chain —> less vigorous the reaction)
— esterification (heat under reflux with concentrated sulfuric acid as catalyst, alcohol + carboxylic acid = ester + water, naming : alcohol —> carboxylic acid)
— dehydration (heated under reflux, aluminium oxide powder/concentrated H2SO4 or H3PO4, product alkene)
— oxidation (primary —> aldehyde —> carboxylic acid, secondary —> aldehyde, tertiary —> nothing, oxidising agent : KMnO4 : purple to colourless , K2Cr2O7 : orange to green)

ester
— hydrolysis (heat under reflux with acid or base, acid —> carboxylic acid + alcohol, base —> salt + alcohol)

carboxylic acids
— formed from nitriles (reflux with DILUTE hydrochloric acid, hydrolysis happens)
— react with alkalis, metals, carbonates
reduction using LiAlH4 in dry ether, room temperature

revise more on
-- products of the reactions
]]> 2021-08-09 07:36:39 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672621657 Jasmine JC2T https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672630769 Revised on the 6 reactions of alcohols :
- combustion ( syllabus only includes complete combustion )
- nucleophilic substitution 
> HCl, SoCl2, PCl3, PCl5 -> heat under reflux
> PCl5 -> room temp
- reaction with sodium metal 
> forms sodium ethoxide, which is a white crystalline solid
- esterification
> alcohol ( ex. Ethyl ) & carboxylic acids ( ex. Ethanoate )
- dehydration 
> using hot Al2O3 or Conc. H2SO4 or Conc. H3PO4
- oxidation
> using KMnO4 -> purple to colourless
> using K2Cr2O7 -> orange to green (nature)

Revised on carboxylic acids :
- nitriles -> reflux with HCl 
- reaction with alkali 
- reaction with reactive metals
- reaction with carbonates
- reduction using LiAlH4 


Need to revise on :
Alcohol reactions and Carboxylic Acid reactions

Teaching was clear and quick, emphasizing on mistakes students often make

]]> 2021-08-09 07:46:03 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672630769 Catherine JC2Truth https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672652521 Revised on:
  • 6 reactions of alcohols (combustion, nucleophilic substitution, reaction with sodium metal, esterification, dehydration and oxidation)
  • Conditions for nucleophilic substitution: PCl5 (room temperature), others (heat under reflux)
  • reaction with sodium metal forms sodium ethoxide (white crystalline solid)
  • esterification: alcohol (ethyl) c.acid (ethanoate)
  • dehydration (hot Al2O3, conc. H3PO4, conc. H2SO4)
  • Primary->Aldehyde->C.Acid, Secondary->Ketone, Tertiary cannot be oxidised
  • C.acid formed from nitriles reflux with dilute HCl
  • Reactions of C.Acid (can be reduced by LiAlH4 in dry ether, room temperature)
Revise more on:
Conditions of nucleophilic substitution and its products.
Teaching: detailed summary (very clear)
]]> 2021-08-09 08:15:58 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672652521 Nevan kho https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672672159 Ive learnt about the reactions for alcohol, carboxylic acid and esters. I also learnt about their relationship by chemical equations. Something new ive learnt is the LiAlH4 in dry ether as a reducing agent. I will need to revise more on the nucleophilic substitution reactions and their catalysts etc.

Teaching was elaborate and concise with examples, tips and tricks. Nice one sir.]]> 2021-08-09 08:43:27 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672672159 Davis JC2Grace https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672673932 I learn about all 6 reactions of Alcohol.(Combustion, Nucleophilic Substitution, Dehydration, Oxidation, Reaction with Sodium and Esterification).

For nucleophilic substitution, all the reactions must be heat under reflux except for PCL5 (rt) .
I also learnt that alcohol can react with sodium but cannot react with sodium hydroxide. 
I also learnt about the basic and acidic hydrolysis of Esters. With acids, the product would be carboxylic acid and alcohol. For hydroxides, the products would be salt and alcohol.
I also learnt the reactions of carboxylic acid as well as the hydrolysis of nitrile to form carboxylic acid.
I need to further review all the reactions in the nucleophilic substitution and the conditions/ reactants for the dehydration,etc.
]]> 2021-08-09 08:46:14 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672673932 Thomson https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672684420 alcohol reactions including dehydration, the halogenation of alcohol (nucleophillic substitution), oxidation of alcohol (secondary alcohol to ketone and primary alcohol to carbohydrate). I need to revise on the substitution of alcohol along with the reagants that react with alcohol during the various reactions stated.]]> 2021-08-09 09:03:14 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672684420 Arwen_JC2 Truth https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672691244 We recalled the formula of alcohol (CnH2n+1OH) and the relation of the number of its R groups with its class (1 - primary, 2 - secondary, 3 - tertianary). We also revised chemical reactions:
  • alcohol combustion (the syllabus focuses on complete combustion): alcohol + oxygen -> carbon dioxide + water
  • nucleophilic substitution: alcohol + hydrogen halide -> halogenalkane + water // HCl must be prepared in situ, SOCl2 is more beneficial as its form as a gas makes it exempt from distillation, PCl5 can be used in temperature; PBr3 and PI3 can be prepared in situ with red phosphorus and bromine and iodine respectively to form bromoalkanes and iodine alkanes
  • ethanol can react with sodium to form sodium ethioxide (forms as a white crystalline solid) and hydrogen gas; longer carbon chains will have a less vigorous reacyion
  • esterification (concentrated H2SO4 as catalyst, heated under reflux)
  • oxidation: primary alcohols can be oxidised to form aldehydes and further oxidised to form ketones, secondary alcohols can be oxidised to form ketones, tertiary alcohols cannot be oxidised

We also recalled the tests for aldehyde and alkenes (KMnO4 acidified (VII); purple to colourless and K2CrO7 (VI); orange to green).

From the quizz, we are reminded that:
  • alcohol can react with sodium but not with sodium hydroxide.
  • hot aluminium oxide, concentrated sulfuric acid under reflux and concentrated phosphoric acid under reflux can be used to dehydrate alcohols into alkenes but not hot acidified potassium manganate.
  • carboxylic acids can be formed from nitriles with being heated under reflux and dilute HCl but not HCl.
  • LiAH4 in dry ethers at room temperature can be used to reduce aldehydes and ketones to alcohols, reduce not carboxylic acids to alcohols.

[I have to understand the reactions and mechanisms at an application level better, especially when displayed and structural formulae are involved.]
]]> 2021-08-09 09:14:03 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672691244 Ella Suita JC2 Grace https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672692845 The reactions of alcohols, esters and carboxylic acid are as follows.

ALCOHOL
  1. Nucleophilic Substitution
The OH group is replaced by the halogen atom. 
a) + HCl:
This reaction is completed under reflux but will not occur for Br and I as they will be further oxidised by the H2SO4 present in situ. RCl and H2O will be formed.
b) + SOCl2:
Completed under reflux. It is convenient as the gaseous products formed, HX and SO2, will escape and distillation is no longer needed.
c) + PCl5:
This is a convenient test for alcohols as it is easily done and observed. It occurs at room temperature and produces RX, HCl and POCl3. A positive test is indicated by the release of white fumes of HCl.
d) + PI3:
In situ with P + I2

2. Combustion
Only complete combustion is involved in the syllabus though incomplete combustion does occur. CO2 and H2O are produced.

3. Reaction with Na
Sodium alkoxide and hydrogen gas are formed. When the excess alcohol has evaporated, a white crystalline solid is formed. 

4. Dehydration 
Catalysts of hot Al2O3, concentrated H2SO4 or H3PO4 must be used through it is not necessary to heat the system under reflux. Alkene and water will be formed.

5. Oxidation
a) Primary ROH
Produces aldehyde which further oxidises to ROOH.
b) Secondary ROH:
Produces ketone and water
c) Tertiary ROH: 
No reaction as C-C bonds are difficult to break.

ESTER
  1. Formation of Esters
The fruity-smelling ester and water are formed when an alcohol reacts with a carboxylic acid using a strong acid catalyst H2SO4 under reflux. Water is liberated from the OH group of ROOH and H of ROH. This reaction is reversible. 

2. Hydrolysis of Esters
This is done by heating the ester under reflux with an acid or a base as catalyst. When a base such as NaOH is used, however, the reaction will complete to form an alcohol and sodium alkanoate, and is not reversible. 

CARBOXYLIC ACID
  1. Formation
Formed through the hydrolysis of nitriles using dilute acid. 

2. Reduction
Using LiAlH4 in dry ether to reduce RCOOH to ROH and H2O

NEED TO REVISE
  • Remembering the reaction conditions and products

TEACHING COMMENT
  • Teaching style is, as usual, concise and not difficult to follow. The explanation of exam style questions has been useful in making sure that we do not encounter difficulties with these questions and make common mistakes.
]]> 2021-08-09 09:16:55 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672692845 Frederic JC2 Truth https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672724088 We recalled about the reactions with alcohol such as nucleophilic substitution with HX, X=Cl/Br/I and the reaction is under refluxed forming RX and H2O
 There is also SOCl2 which is also under refluxed but the difference is that the products are all gases therefore, distillation is not required and the products formed are SO2, sulfur dioxide and HX.
 PCl5 is a simple and convenient test for it requires no heating  and will from HCl, POCl3 and the RX. A positive test indicates white fumes.
 PCl3 requires heating and in situ forming the products RX and H3PO4.
 Oxidation
-Primary alcohols will oxidize into aldehyde(CHO) and further oxidize to carboxylic acids(COOH)
-Secondary alcohols will oxidize into ketones(COCH3)
-Tertiary alcohols will not oxidize
reagent: Potassium dichromate IV, orange to green( K2Cr2O7)
                Potassium manganate IV, purple to colourless( KMnO4)
Reaction with Na:


  • Acids react with metals to produce hydrogen gas and a salt. Alcohols are very weak acids, so they undergo this reaction as well

  • When sodium metal is added to ethanol, the sodium metal sinks and bubbles of hydrogen gas are observed and the salt formed is sodium ethoxide, a white solid

2CH3CH2OH + 2Na = 2CH3CH2O-Na+ + H2

  • This reaction can be used as a test for hydroxy, OH group because if bubbles are observed, then a hydroxy group are present
Alcohols also cannot react with NaOH

Esters: require concentrated sulfuric acid under reflux and water is formed creating an ester bond and it is reversible with an acid unless a base is present because the acid will react with the base to form salt and water. 

For carboxylic acids:
Reagent: Lithium tetrahydriodoaluminate, LiAlH4 or sodium tetrahydriodoaluminate, NaBH4

Condition: For LiAlH4 - dry ether

                      For NaHB4 - in aqueous alcoholic solution 

Product: Aldehyde - primary alcohol

                  Ketone - secondary alcohol

  • LiAlH4 and NaBH4 are acting as reducing agents as well as providing the nucleophile, H-. This is a redox reaction as well as a nucleophilic addition reaction

  • For aldehydes, primary alcohols are formed upon reduction

Overall, the lecture is great and with the help of drawings and the presentation. Information could be taken in more easily


]]> 2021-08-09 10:12:32 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672724088 Ryan JC2Truth ryanant2004 https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672728343 I learn about the different reactions of alcohol, such as nucleophilic substitution with hydrogen halide and the reaction under refluxed with H2O and RX. We also learn about the oxidation of alcohol, where secondary alcohol oxidize into ketone and primary alcohol oxidize into aldehyde and further oxidize into carboxylic acid. We also learned about the combustion of alcohol and the reaction of alcohol with sodium.   I learn that all nucleophilic substitution with alcohol must be heat under reflux except for PCL5, where the reaction can be done in room temperature. I also learned about esterification, where alcohol reacts with carboxylic acid to form esters. Ester will react with acid to form carboxylic acid and alcohol, while ester will react with hydroxides to form salt and alcohol. 

I need to further review more about the different type of reactions with its conditions. Overall the teaching was easy to understand and it was fun.

]]> 2021-08-09 10:21:58 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672728343 Josh JC2Truth https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672728664 We learnt about the reaction of alcohols, esters and carboxylic acids today. Specifically on oxidation, nucleophilic substitution, reaction with sodium metal, esterification, dehydration and oxidation.
Complete combustion has a product of carbon dioxide and water.
Nucleophilic substitution with hydrogen halides produce a halogenoalkane and water when heated under reflux.
Example: NaCl + H2SO4 + NaHSO4 + HCl
Where concentrated H2SO4 is used
If using SOCl2 and heated under reflux, the other two products are gases which allows the collection of halogenoalkane to be easy.
Nucleophilic substitution with PCl5 conditions and results: Room temperature, steamy fumes released. Test for hydroxyl groups and products are halogenoalkanes, HCl, POCl3
Nucleophilic substitution with PCl3 (heat under reflux)
Nucleophilic substitution with PI3 and PBr3 (heat under reflux, in situ using red phosphorus and bromine/iodine, product is H3PO3)
Reactions with sodium metal is similar to the reaction of sodium and water but less vigorous. Sodium ethoxide salt forms a white crystalline solid when excess ethanol is evaporated off. The longer the hydrocarbon chain, the less vigorous the reaction.
Esterification is the reaction between alcohol and carboxylic acids. It uses concentrated sulfuric acid as a catalyst and heated under reflux. 
Dehydration is when alcohol vapor is passed through hot catalyst of aluminum oxide powder. Other catalysts such as concentrated sulfuric acid and phosphoric acid can also be used. 
Primary alcohol oxidized to aldehyde and further oxidized to carboxylic acids.
Secondary alcohol is oxidized to ketone.
Tertiary alcohol cannot be oxidized.
Esters are made by hydrolysis with heat under reflux with an acid or base.
Carboxylic acids are formed from nitriles and heat under reflux with dilute hydrochloric acid as well as hydrolysis.
Carboxylic acids can react with alkalis, reactive metals, carbonates and cab be reduced using lithium tetrahydridoaluminate, LiAlH4 in dry ether at room temperature.

The lesson was good and easy to follow with a clear powerpoint presentation. I need to revise more on the conditions. (Catalysts, temperature, concentration, etc.)]]> 2021-08-09 10:22:44 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672728664 Nathan L JC2Truth https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672731326 We revised again about the reaction that involves Alcohol starting with Combustion, Reaction with Sodium, Dehydration, Nucleophilic substitution, Oxidation as well as esterification. We also relearned about the certain conditions such as the nucleophilic substitution requires hot PCL5 as a catalyst. Also revised on the tests to test the presence on Aldehyde as well as Ketones, the color changes of KMnO4, purple to colorless, and K2CrO7, orange to green.

Overall the explanation and the teaching is very clear and everything is thoroughly explained. It was spot-on.]]> 2021-08-09 10:27:52 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672731326 Benedict JC2 Truth https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672732016 Alcohol
- alcohols undergo complete combustion and in this syllabus, we asume that all alohol undergo complete combustion
[Nucleophilic substitution]
- Alcohols undergo nucleophilic substitution with hydrogen halides. This process must be heated under reflux with concentrated H2SO4 used.
- Alcohols can undergo nucleophilic substitution using SO2 where the hydrogen halide is instead bonded with SO. In this reaction, it must be heated under reflux and comes with benefits. When using hydrogen halides, A halogenoalkane will be formed along with water. The water can be seperated when the solution undergoes distillitation. When using SOR, the product will be the halogenoalkane along with a hydrogen halide and SO2 which both will be in gaseous form. This allows for you to obtain the Halogenoalkane alot easier
- Using PCl5. Using PCl5, we can use it to test alcohols due to the steamy white fumes produced by the HCl produced. It is also all done under room temp. The products include hydrochloric acid and POCl3
*PCl3 can also be used but, the system must be heated under reflux.
*When using PBr3 or PI3, the reaction must be done in situ with red phosphorous heated under reflux.
[Sodium]
When alcohols react with sodium, the hydroxide will have the hydrogen atom replaced. The sodium ethoxide salt forms a white crystaline solid when excess sodium is evaporated off.
[Esterification]
-It forms due from the reaction of alcohols and carboxylic acids. Concentrated sulfuric acid is used as a catalysy and is heated under reflux.
-Ester (Sweet,Fruity smell)
[Dehydration]
-Alcohol vapour passed through hot catalyst of Al2O3 powder or concentrated H2SO4 or H3PO4
-Will result in an alkene
[Oxidation]
-Primary alcohol oxidised to aldehyde and further oxidised to carboxylic acid.
-secondart alchool ocidised to ketone
-tertiary alcohol cannot be oxidised
-oxidising agents and observations
KMnO4 acidified (VII): Purple -> Colourless
KCr2O4 acidified (VII): Orange -> green
[Hydrolysis]
-Heat under reflux with acid or base
-When esters are heated with acid, it will result in a product of carboxylic acid and alcohol.
-When the esters are heated with a base, It will result in a product of a salt with the alkaline metal with an alcohol.
Carboxylic Acids
-Forms from nitriles
-heat under reflux with dilute hydrochloric acid 
-Hydrolysis happens
ex: CH3CH2CN + HCl + 2H2O -> CH3CH2COOH + NH4Cl
[Reactions]
Reduction using LIAlH4 (Lithium tetrahydridoaluminate) in dry ether (reacts vigorously with water so dry ether is needed) at room temp. (very good reducing agent so there is no need to heat up.

Mr Gopi's lesson was very clear and informative. I was able to revise and understand alot of what i couldn't in the last school year. I mostly recalled of what the interactions of the organic compounds were and the mechanics behind them. More importantly, i learnt about all the conditions the reactions need to be in. I could not ask for a better teacher.

]]> 2021-08-09 10:29:26 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672732016 Chris JC2Truth https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672732420 We learnt about the properties and reactions of halogenoalkanes, alcohols and carboxylic acids. We learnt about the various mechanisms of the reactions that occur with these functional groups, including nucleophilic substitution, elimination, esterification and hydration]]> 2021-08-09 10:30:23 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672732420 Josh JC2 Grace https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672736002 I Tried to clear up my misconceptions on whether a reaction is done under reflux or not.

Oh and I was reminded on the TERRIBLY LONG list of nucleophilic substitution reactions alcohols undergo]]> 2021-08-09 10:38:43 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672736002 Jonathan JC2G https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672736032 We learnt the reactions and properties of alcohols. I think that something important to remember is the test for it, and why it is used. Another thing is how alcohols are formed, and what they can form. They undergo combustion, elimination, nucleophilic substitution, elimination, esterification and hydration.]]> 2021-08-09 10:38:46 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672736032 Jacksen JC2T https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672742017 Learned a lot, prob too much cuz most of these stuff werent taught to me back in JC1 

Learned about 
- alcohol
-carboxylic acid
-ester 
- different reactions and their conditions such as 
esterification , dehydration , elimination, oxidation and reduction of primary/secondary alcohol  Reaction with Na ion(and how alcohol cant react with NaOH) and nucleophilic substitution.]]> 2021-08-09 10:51:15 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672742017 Wilson JC2T https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672751971 Today, we revised on alcohols, esters and carboxylic acids along with each of their long list of reactions. Alcohols can be reduced to alkenes using Al2O3 and concentrated H2SO4. It can also react with sodium to form sodium alkoxide. Other than that, it can undergo nucleophilic substitution with PCl3, PCl5 and SOCl2 to form Halogenoalkanes. It can also be oxidized either by K2Cr2O7, H2SO4 or KMnO4 to form ketones, aldehydes or even be further oxidized to form carboxylic acids. For esters, we learnt that it can only be formed through the reaction of alcohols and carboxylic acid in the presence of concentrated H2SO4. It can however undergo hydrolysis to form alcohol and carboxylic acid(acidic) or carboxylate ions. Other than the hydrolysis of ester, oxidation of aldehydes can also form carboxylic acids. Carboxylic are reduced by LiAlH4 to form primary alcohol. It can also undergo all the basic reactions of an acid.]]> 2021-08-09 11:12:17 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672751971 Ashley JC2 Grace https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672765794 Ahh I learnt a lot about the different Nucleophilic Substitutions reactions of alcohol! (Except PCL5 that takes place in room temperature and steamy fumes as an indicator of OH group), the reactions with HCL, SOCL2 and PCl3 requires heat and needs to be in reflux ( + needs to be distilled, does not need to be distilled). We also learnt abt esterification, acidic hydrolysis being reversible and alkaline hydrolysis being irreversible and producing salt and alcohol ( bc carbo. acid will react w/ the acid). Carboxylic acids behave like any other acid in reaction (so nothing that new there), but it's formed from nitriles and hydrochloric acids. ]]> 2021-08-09 11:37:48 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672765794 Megan Jc2 T https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672774883 During this lesson I was able to review about :
  • Nucleophilic substitution of alcohols using HCl, SOCl2, PCl5, PCl3, PBr3, and PI3.
  • The meaning of in situ : formed in the same vessel
  • Reaction of alcohol with sodium to form sodium alkoxide and hydrogen
  • The reaction esterification which requires heated under reflux and concentrated sulfuric acid 
  • How to name esters 
  • Hydrolysis of esters 
  • Dehydration of alcohol that forms alkenes
  • Oxidation reactions of primary and secondary alcohols
  • Formation of carboxylic acid using nitriles and HCl. 

What to revise: 
  • Remember the reactions on how colour changes during oxidation reactions of alcohols
  • The products and conditions in nucleophilic substitution 

Comment: The lecture was very well paced, it was a good refresher for this chapter as it emphasized on the very important parts and I believe it covered the learning objectives very well. Would rate the teaching style 11/10.
]]> 2021-08-09 11:52:19 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672774883 Geoffrey Jc2Truth https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672777495 Today we revised about the chapter alcohols, esters, carboxylic acids and their reactions. 
There are 6 Types of reactions for alcohols:
1.Combustion: When alcohols react with oxygen and form CO2 and H2O.Incomplete combustion may also occur and form CO and H2O. 

2.Nucleophilic Substitution: Is when 
Alcohol + hydrogen halide forming halogenoalkane + water 
with conditon for  HCl, SoCl2, PCl3, PCl5 -> heat under reflux 

3.Reaction with sodium metal is when alcohols react with soudim metals reaction includes: 
-No reaction with sodium hydroxide 
- Product : Salt + Hydrogen (g) 
- Sodiun ethoxide salt : white crystalline solid
-Less reactive - longer carbon chain , non polar, difficult for oxygen and hydrogen to break 

4.Esterification: Reaction between alcohol and carboxylic acids, using concentrated sulfuric acid as catalyst and heated under reflux

5.Dehydration: To remove water from alcohols, Alcohol vapour is passed through hot catalyst of aluminium oxide 
powder/ concentrated H2SO4or H3PO
6.Oxidation:
-Primary alcohol oxidized to aldehyde and further oxidized to 
carboxylic acids
-Secondary alcohol is oxidized to ketone
-Tertiary alcohol cannot be oxidized
oxidising agents and observations reagent: KCr2O7 orange to green
KMnO4 purple to colourless

Esters:  formed when an alcohol reacts with a carboxylic acid using a strong acid catalyst H2SO4 under reflux
-Hydrolysis occurs when heating the ester under reflux with an acid or a base as catalyst. 

Carboxylic acid:
-Formation
Formed through the hydrolysis of nitriles using dilute acid. 

-Reduction
Using LiAlH4 in dry ether to reduce RCOOH to ROH and H2O

Need to revise on memorizing the reactions

Lecture was fast, clear and helped me recall the information i forgot
]]> 2021-08-09 11:56:25 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672777495 Keira JC 2 Grace keiramadeline https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672794871 I learned the reactions of alcohol, esters, and carboxylic acids
Alcohols produce halogenoalkane in a nucleophilic substitution reaction, and I learned that the reaction with SOCl2 is easier to collect since other products produced are in a gaseous state, while the reaction with PCl5 is also the only one done at room temperature. Salt is produced when reacting with sodium metal but alcohols cannot react with sodium hydroxide. Alcohols react with carboxylic acid to produce esters and can also make alkenes when dehydrated with hot aluminum oxide, concentrated sulfuric, or phosphoric acid.
Esters undergo hydrolysis when heated under reflux with acid or base, but the reaction with a base produces a salt and is not a reversible reaction. 
Carboxylic acids can be formed from nitriles when heated under reflux with dilute hydrochloric acid. LiAlH4  in dry ether reduces carboxylic acid to form primary alcohols.

I need to further review the reactions and their conditions but today's lesson helped me understand the topics more and cleared the doubts I had.]]> 2021-08-09 12:18:13 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672794871 James EC JC2 GRACE https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672799459 For this lesson i reviewed alcohols and carboxylic acids. For alcohol there is primary secondary and tertiary. primary has 1 R group, secondary has 2 while tertiary has 3. Remember to draw it out before assuming as could be careless. Then there were reactions. There was Combustion, Nucleophilic substitution, Reaction with sodium metal, Esterification, Dehydration and Oxidation. For combustion in our syllabus its said to be complete but that does not mean cannot incomplete.  For complete combustion the products are CO2 and H2O while incomplete is CO and H2O. For Nucleophilic substitution HCl and SOCl2 both under reflux. Must revise again for the rest, really focusing for the products and specific details. Remember about hair gel thing for colour change: KMnO4 purple to colourless while KCr2O7 orange to green





]]> 2021-08-09 12:24:34 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672799459 Owen-JC2T owennicholasyap https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672809469 Alcohols can undergo 6 different reactions Combustion, Nucleophilic substitution, Reaction with Na, Esterification, Dehydration and oxidation

Combustion
- When alcohols are combusted, the product Is always CO2   gas and H2O

Nucleophilic Substitution
- Condition: Heated under reflux + Conc H2SO4
- CH3CH2OH + HCl → CH3CH2Cl + 3H2O

Sodium metal
- The longer the carbon chain, the less vigorous the reaction
- C2H5OH + Na -> C2H5O- Na+ + H2

Esterification
- Condition: Using concentrated sulfuric acid as catalyst and heated under reflux
- Esters have a sweet/fruity smell
- Reaction between alcohol and carboxylic acid

Dehydration
- Condition: aluminium oxide powder/concentrated H2SO4 or H3PO4
-C2H5OH -> CH2=CH2 + H2O

Oxidation
- Primary alcohol oxidized to aldehyde and further oxidized to
carboxylic acids
- Secondary alcohol is oxidized to ketone
- Tertiary alcohol cannot be oxidized

Need more practice on:
memorizing conditions, understanding esters and the color changes






]]> 2021-08-09 12:36:32 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672809469 Nicholas_JC2Truth https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672810493 I was able to recall the reactions of alcohol, ester and carboxylic acid. I learned that alcohol can have incomplete combustion but in our syllabus, it is assumed to always have complete combustion as the reaction. ]]> 2021-08-09 12:37:35 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672810493 Kevin https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672810790 I am able to recall the conditions of the reaction of nucleophilic substitution of alcohol and HCl,SOCl2,PCl5,PCl3,PBr3,PI3.
For PCl5 rtp, PCl3 heat, SOCl2, heat under reflux, the rest in situ and heat under reflux. Nitriles can be hydrolised to form carboxylic acid in dilute H2SO4, carboxylic acid can react with Na,NaOH, and carbonate salts]]> 2021-08-09 12:37:58 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672810790 Jennifer JC1G https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672820629 - Alcohol formula is CnH2n+1OH
- Can be primary, secondary or tertiary
- Six types of reactions 

1. Combustion 
- Always complete 

2. Nucleophilic Substitution
+HCl
- Product is Halogenoalkane & Water
- Heated under reflux

+H2SO4
- Concentrated 
- Product is HCl
- Prepared in situ

+SOCl2
- Heated under reflux

+PCl5
- Room temperature 
- Steamy white fumes (test for hydroxyl group)

+PCl3
- Same as PCl5 but needs more heating

+PBr3
- Product is bromoalkane & H3PO3
- In situ
- Use red phosphorus & bromine 

+PI3
- Product is iodoalkane & H3PO3
- In situ
- Use red phosphorus & iodine

3. Reactions with sodium metal
- Less vigorous 
- White crystalline solid
- The longer the hydrocarbon chain, the less vigorous the reaction 
- CANNOT react with NaOH

4. Esterification
- Alcohol + Carboxylic acid --> Ester + Water
- Ester has sweet fruity smell
- Catalyst : Concentrated H2SO4
- Heated under reflux 

5. Dehydration 
- Product is alkene & water 
- Catalyst : Hot Aluminium oxide power OR Concentrated H2SO4/H3PO4

6. Oxidation 
- Primary alcohol can be oxidized into aldehyde then to carboxylic acid
- Secondary alcohol can only be oxidized into ketone 
- Tertiary alcohol no reaction 

Summary of Esters
- Hydrolysis
- Heat under reflux
- Use acid or base

Summary of Carboxylic acids
- Formed from nitriles 
- Heated under reflux 
- Use dilute HCl
- Hydrolysis occurs
- Weak acids
- Can react with :
1. Alkali
2. Reactive metals (Ex : Mg)
3. Carbonates
- Can be reduced using LiAlH4 in dry ether 
- Room temperature

What I need to improve on 
- Recognizing the different reactions 
- Recognizing the catalysts & other conditions needed
- Recognizing which cannot react

Comments on teaching 
- Good :)]]> 2021-08-09 12:50:25 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672820629 Cleantha JC2G https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672824326 We revised about the reactions of alcohol which includes:
• Combustion
• Nucleophilic Substitution 
• Reaction with Sodium Metal
• Esterification 
• Dehydration 
• Oxidation 

For Nucleophilic Substitution, it is often mistaken that the reaction between alcohol and HCl will be done at room temperature but it is actually heated under reflux.
When reacting with sodium hydroxide, reaction will not occur
For oxidisation, the oxidising agents will be:
                           • potassium permanganate:       purple to colourless
                           • potassium dichromate: 
Orange to green
]]> 2021-08-09 12:54:49 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672824326 Angela jc2g https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672827548 - Incomplete combustion is not in our syllabus, so it is always complete combustion
- HCl is prepared in situ using concentrated H2SO4
- Benefit of using SOCl2 is that gas is produced so there is no need to do distillation and it would be easier to collect the choloroalkane
- Benefit of using PCl5 is that we do not need to heat them
-  Alcohols can react with sodium metal but not sodium hydroxide
- In esterification, the hydrogen comes from the alcohol
- Conditions for dehydration: hot aluminium oxide or concentrated sulfuric acid or concentrated phosporic acid
- Tertiary alcohol cannot be oxidised
- Carboxylic acids react with alkalis, reactive metals and carbonates
- Dilute HCl must be used for reduction reaction 
- LiAlH4 is a very good reducing agent that the reaction will take place in room temperature

I need to learn more about the nucleophilic substitution reactions and reactions of carboxylic acids

As usual, mr Gopi's teaching is super good! He was able to cover a lot of things in a short time.]]> 2021-08-09 12:57:44 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672827548 Dylan JC2G https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672827580 Today, in chemistry class, the main topics were about Alcohol, Esters & Carboxylic Acid. Starting off with Alcohol,

- General Formula: CnH2n+1OH
 - Primary Alcohol -OH (bonded to 1R Group)
 - Secondary Alcohol (bonded to 2R Group)
 - Tertiary Alcohol (bonded to 3R Group) 

the different types of reactions of alcohol which includes:
1. combustion
- CO2 and H2O are produced

2. nucleophilic substitution
- with HCl (heated under reflux, HCl is prepared in situ [alcohol + NaCl + H2SO4; where the NaCl+H2SO4 reacts in situ to form NaHSO4 + HCl and the HCl reacts with the alcohol])
- using SOCl2 (heated under reflux, more beneficial than HCl as very easy collection since the remaining products from this reaction are all gases so leaving halogenoalkanes behind, hence no distillation needed)
- using PCl5 (room temperature, release of steamy white fumes which is tested for hydroxyl group)
- using PCl3 (heated under reflux)
- using PBr3/PI3 (heated under reflux, formed in situ, formation of bromoalkanes/iodoalkanes)

3. Reaction with Na
 - similar to reaction of sodium & water but less vigorous
 - Sodium ethoxide salt (white crystalline solid) and hydrogen gas are formed. 
*side note: alcohol does not reaction with NaOH

4. Esterification
- reversible reaction
- reaction of alcohol & carboxylic acids (using conc. H2SO4 as catalyst and heated under reflux)
- ester formed are sweet and fruity
- naming esters; first alcohol then carboxylic acid so eg.  ethyl + propanoic acid gives ethyl propanoate 

5. Dehydration 
- alcohol vapour passed through hot catalyst of aluminium oxide/ conc. H2SO4 or H3PO4 to form alkene and water

6. Oxidation
- primary alcohol -> aldehydes -> carboxylic acid
- secondary alcohol -> ketone
- tertiary alcohol -> cannot be oxidized
acidified KMnO4(VII): purple -> colourless
acidified K2Cr2O7(VI): orange -> green

Esters
(how esters are formed has been discussed earlier on)
- reaction by hydrolysis
- heat under reflux with acid or base
- acid -> reversible reaction
- base -> not reversible 
*note: base reacts with carboxylic acid after Hydrolysis

Carboxylic Acids
- formed from nitriles + dilute HCl that is heated under reflex 
- hydrolysis reaction
Reactions include:
- weak acids
- reaction with alkalis
- reaction with reactive metals
- reaction with carbonates
- reduction using LiAlH4 in dry ether at room temperature to form primary alcohol (no heat under reflux as it is very reactive already)
- CH3COOH + 4[H] -> CH3CH2OH + H2O

What to revise on:
-        The products and conditions in nucleophilic substitution 
-        Recognizing the different types of reactions (There are A LOT ☹ )

Comment for Mr. Gopi :D
Today’s class was fun and interesting as usual and there’s nothing that I’d like to change about it. One of the things I really enjoy about Mr Gopi’s class is that he always manages to explain everything before the period end. He also records the lessons and I find that really useful if I ever missed a point in the lesson- so thank you sir!

]]> 2021-08-09 12:57:46 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672827580 Earlene JC2G https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672828617 alcohols

1. types: primary, secondary, tertiary

2. combustion (always complete according to our syllabus)

3. nucleophilic substitution (all is done in situ and heated under reflux except for the one with PCl5)

4. preparation of HCl: NaCl + conc. H2SO4 (for reaction of alcohol with hydrogen halide) (preparation of HCl is in situ)

5. Reaction with SOCl2 is useful as it allows for easier collection of halogenoalkane as other products are in gaseous form.

6. Reaction with PCl5 is rather special: it is done at room temperature and white steamy fumes are produced which is a good test for presence of alcohols.

7. You can use PCl3 instead of PCl5 but it requires heating, hence PCl5 is the one being used to test for alcohols.

8. For manufacture of bromoalkanes or iodoalkanes, PBr3 and PI3 is used respectively and these are prepared in situ while heated under reflux.

9. Heating under reflux is used to prevent volatile compounds from escaping to the environment, ex: alcohols. This ensures continuous reaction until the reaction is complete.

10. Alcohols react with sodium but not with sodium hydroxide. Reaction with sodium gives sodium ethoxide salt which is a white crystalline solid that forms as the excess alcohol is evaporated off.

11. esterification (alcohol + carboxylic acid) (H is from alcohol, OH comes from carboxylic acid) (catalyst is conc. H2SO4 and reaction occurs while heated under reflux)

12. Esters are named by ....yl ....anoate (first part comes from alcohol, second part is from carboxylic acid, ex: ethanol with propanoic acid gives ethyl propanoate)

13. dehydration (alcohol becomes alkene) (catalyst is hot Al2O3 / conc. H3PO4 / conc. H2SO4 and reaction is done while heated under reflux)

14. oxidisation (primary alcohol becomes aldehyde then carboxylic acid, secondary alcohol becomes ketone, tertiary alcohol cannot be oxidised) (oxidising agent is acidified KMnO4 — purple to colourless / acidified K2CrO7 — orange to green)

esters

1. hydrolysis (heated under reflux with conc. H2SO4) (reversible reaction for acid, carboxylic acid and alcohol produced) (when base is used, carboxylic acid and alcohol is produced but the carboxylic acid reacts with the base to give a salt, hence the reaction is not reversible)

carboxylic acids

1. How to get: Halogenoalkane reacts with KCN to form nitrile. Nitrile is heated under reflux in the presence of dilute acid — water from dil. acid is needed. Hydrolysis happens, nitrile is changed into carboxylic acid.

2. reactions of carboxylic acid (generally the same as any other acids)

3. reduction (carboxylic acid  is reduced to primary alcohol with LiAlH4 in dry ether at room temperature — reaction of LiAlH4 is very vigorous with water) (alkaline NaBH4 reduces carboxylic acid as well but it is not as good of a reducing agent as LiAlH4)

things i need to review on

1. memorising all the different conditions for the different reactions

feedback for Mr. Gopi

The lesson was very informative and it really helped me to recap all of the stuff we learnt last semester. It was also nice to have th recording of the lesson to refer back to. The quizziz music gives us anxiety sir 🥲. Overall I really liked the lesson today, thank you sir !! 🤩]]> 2021-08-09 12:58:59 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672828617 Audrey JC2T https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672833918 I recalled on 
- the list of reactions that alcohol can undergo : combustion, nucleophilic substitution 
- HCl prepared in situ (NaCl + conc. H2SO4) to form RCl and water
- SOCl2 (heated under reflux)
-PCl3 (heated under reflux)
-PCl5 (room temp, steamy fumes released) (used as test for alcohol)
-PBr3 (heated under reflux) (PBr3 prepared in situ)
-PI3 (heated under reflux)(PI3 prepared in situ)
-Sodium (the longer the chain, the less vigorous the reaction)
-esterification (alcohol + carboxylic acid with conc. H2SO4 under reflux)
-dehydration (conc. H2SO4 /Al2O3/H3PO4)
I also recalled on the different reactions to make carboxylic acid :
-(oxidation of primary alcohol and aldehyde, acid alkali hydrolysis of nitrile) and its reactions. -LiAlH4 can also he used to reduce carboxylic acid into aldehyde and primary alcohol.]]> 2021-08-09 13:04:45 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672833918 michelle JC2G https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672845683 today i learnt the reactions of alcohol:

combustion:
  • alcohol burns in the presence of oxygen to form carbon dioxide and water

nucleophilic substitution:
  • all reactions are in situ
  • alcohol with pcl5 carried out in room temperature , white steamy fumes produced
  • the rest are heated under reflux

reaction with sodium:
  • ethoxide salt produced, white crystalline solid will be formed

dehydration:
  • temperature: 170 degrees
  • catalyst: concentrated sulfuric acid/ conc. phosphoric acid/ hot aluminum oxide
  • no need to be heated under reflux, it is a direct reaction
  • produces alkene and water

oxidation:
  • oxidizing agents: acidified KMnO4( purple to colourless) ,K2Cr2O7(orange to green)
  • primary alcohols are oxidised to form aldehydes which are further oxidised to form carboxylic acid
  • secondary alcohols are oxidised to form ketones
  • tertiary alcohols cannot be oxidised.

esterification:
  • reaction between alcohols and carboxylic acid
  • heated under reflux
  • catalyst: conc. sulfuric acid
  • produces ester and water

what i need to revise more:
  • probably memorizing certain equations because i tend to forget them. 

comments on teaching:
  • it was just like previous teachings, mr gopi reviewed the materials with us and then discussed some past year paper questions that he has selected for us. overall it was a great class and it refreshed our minds about alcohols again since we might have forgotten important parts of it.
]]> 2021-08-09 13:15:52 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672845683 Jusitn JC2G https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672963206 Today there was a lecture on Alcohol,Ester and carboxylic acids

Alcohol can completely combust in oxygen to create carbondioxide and water

Halogenoallkanes can undergo nucleophilic substitution.
Nuclopilic substitution is the nucleophyle will substitute something
 
There are 3 types of reaction
-Elimination using NaOH(aq) or AgNO3(aq)
-Using KCN 
-Using excess amonia 

HCl is prepared in situ(same reaction chamber)
NaCl +H2S04(concentrated)-> NaHSO4+HCl
C2H5OH + SOCl2 -> C2H5OH + HCl(g) + SO2(g)

Reaction with SOCl2 will make collection easier since HCl and SO2 are in gas form

PCl5 can be used to test hydroxyl groups in room temperature. Apparently the reaction of PCl5 in room temperature is very important info and Mr.Gopi said to remember this and forget everything else.

C2H5OH + PCl5 -> C2H5CL+ HCL(g) +POCL3

In this reaction, the white fumes of hydrogen chloride gas is a good indication that there is a hydroxyl group. This reaction is more convinient than other reactions because it can be done in room temp

Reactions of PCl3 needs to be heated under reflux
To create ioodoalkane and bromo alkane we can use PI3 and PBr3 respectively
H3PO3 is always part of the products


Alcohol reactions with sodium metal 
C2H5OH + Na+ = C2H5ONa(sodium ethoxide) + H2
This reaction forms white crystaline solids.
The longer the carbon chain the less vigorous the reaction. 

Esterification
Reaction of alcohol and carboxylic acid using conc H2SO4 as catalyst and heated under reflux. Esters have sweet and fruity smell

Dehydration(removal of water molecule)
conditions
-heated under reflux
-hot catalyst of aluminium oxide Al2O3
-uses concentrated H2SO4 and H3PO4

Oxidation 
Primary oxidised to aldehyde
Secondary oxidies to ketone
Tertiary cannot be oxidised

Oxidising agent can be KMnO4(Purple to colourless) or K2Cr2O7(orange to green)

Esters 
Hydrolysis (heat under reflux with acid or base)

Carboxylic acid
nitrile + dilute hydrochlric acid ]]> 2021-08-09 14:44:44 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672963206 Chem reflection Jordan Jc2G https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672987169 Today I learnt about the reactions if alcohols,esters and carboxylic acid.

Alcohol undergoes combustion,nucleophilic substitution, reaction with Na but not NaOH, esterification, dehydration and ocidation.

For alcohol, it has 4 main nucleophilic(Definition: Species that contains a lone pair of electrons) substitution reaction:

1. Reaction with hydrogen halide: Forms a halogenoalkane and water
Conditions: HCl prepared in situ,heated under reflux

2. Reaction with SOCl2: Forms a halogenoalkane, HCl(g) and SO2(g)
Conditions: Heated under reflux
Benefit: Halogenoalkane can be collected easily

3. Reaction with PCl5: Forms Halogenoalkane, HCl and POCl3
Conditions: Room tenperature
Benefits: Product consists of white steamy fumes and as it happens at rt, it can identify whether reactant is an alcohol.

4. Reaction with PX3: Forms bromoalkanes, iodoalkanes and chloroalkanes depending on reactant used. Also H3PO3 is formed.
Conditions: in situ, heated under reflux

Alcohol can undergo reaction with sodium but not sodium hydroxide. Hydrogen and Sodium ethoxide salt(RO^-Na^+) are formed. Sodium ethoxide is white crystalline solid when excess alcohol is evaporated.

Alcohol can undergo esterification ( Alcohol + Carboxylic acid = Ester + water)
Conditions: Sulphuric acid as catalyst and heated under reflux
OH- is taken from carboxylic acid and H+ is taken from alcohol. 
Naming of ester: Alcohol + carboxylic acid

Alcohol can undergo dehydration: Forms alkene and water
Conditions: Heated Al2O3, concentrated H2SO4, comcentrated H3PO4

Alcohols can undergo oxidation: 
KMnO4: purple to colourless
K2Cr2O7: Orange to green

Primary alcohol—> Aldehyde—>Carboxylic acid
Secondary alcohol—> ketone
Tertiary alcohol: no reaction

Esters can be hydrolized and heated in reflux to form its products as it is a reverible reaction.
With acid: Carboxylic acid + alcohol
With base: salt + alcohol

Carboxylic acids can be formed from nitriles by hydrolysis.
Conditions: Heat under reflux with dilute HCl

Carboxylic acids are weak acids.
They react with alkali, reactive metals, carbonates.
Carboxylic acids can be reduced using LiAlH4 or NaBH4 depending on the need.

]]> 2021-08-09 15:03:12 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1672987169 Lindsay JC2G mwm6s5yc99 https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1673824467 i reviewed the chapters that we have learned before including the 6 types of reactions that alcohol can go through : Combustion, substitution, elimination, oxidation, reaction with Na and Esterification. I was also able to memorise its different reagents and conditions required for the reaction to occur.

For esters, I learned its basic properties such as liquid at room temperature, fruity smelling, insoluble in water, etc. I also learned the hydrolysis reaction which is
Ester + Alkali (aq) -> salt + Alcohol

For carboxylic acids, I learned the different reactions which are: Neutralisation, displacement, reduction, esterification. ]]> 2021-08-10 06:59:17 UTC https://padlet.com/pooganeswaripiks/v0zrmfqfvv2hlpav/wish/1673824467