Organic Chemsistry 2

Question 1

Acid hydrolysis of esters:

Ester + H2O —–>

Answer 1

Carboxylic acid + ethanol

You need to reflux ester with dilute acid

Question 2

Base hydrolysis of esters:

Ester + OH- ——>

Answer 2

Carboxylate ion + alcohol

Reaction is done under reflux

Question 3

Oxidation of Alcohols and Aldehydes:

Answer 3

Alcohol —-> aldehyde + H2O —-> carboxylic acid

Acidified potassium dichromate is used

Question 4

Hydrolysis of nitriles

Answer 4

Nitrile + H2O + HCl —-> carboxylic acid + NH4Cl

Reflux of nitrile is required

Question 5

Neutralisation of carboxylic acids

Answer 5

Carboxylic acid + NaOH —> salt ( sodium ethanoate) + H2O

Question 6

Acyl Chlorides and Amines

Answer 6

Acyl chloride + Amine —> N-substituted amides + HCl

Question 7

Acyl chloride and alcohol

Answer 7

Acyl chloride + alcohol —-> ester + HCl

Question 8

Acyl chloride and water

Answer 8

Acyl chloride + H2O —-> carboxylic acid + HCl

Question 9

Acyl chloride and concentrated ammonia

Answer 9

Acyl chloride + Conc. Ammonia –> amide + HCl

Question 10

Carboxylic acids reacting with metals

Answer 10

Carboxylic acid + sodium—> salt ( sodium ethanoate ) + H2

Question 11

Carboxylic acids reacting with carbonates or hydrocarbonates

Answer 11

Carboxylic acid + carbonate —> salt + H2O + CO2

Question 12

Heating carboxylic acid with alcohol

Answer 12

Carboxylic acid + alcohol —> ester + H2O

Acid catalyst used ( conc. H2SO4 ) reversible reaction

Question 13

Reduction of carboxylic acids

Answer 13

Reduce carboxylic acid using LiAlH4 in Dry Ether to form a primary alcohol

Carboxylic acid—-> primary alcohol

Question 14

Carboxylic acids reacting with PCl5

Answer 14

Carboxylic acid + PCl5 —-> acyl chloride + POCl3 + HCl

Question 15

Reacting an acid anhydride with an alcohol

Answer 15

Acid anyhydride + alcohol —> ester + carboxylic acid

Question 16

What is a racemic mixture

Answer 16

It contains equal amounts of each enantiomer of a chiral compound

Question 17

Why don’t racemic mixtures rotate plane of polarised light?

Answer 17

This is because the two enatiomers cancel each other’s light rotating affect

Question 18

Why do chemists react 2 achiral mixtures together

Answer 18

So they can get a racemic mixture of a chiral product

So when they react there’s an equal chance of forming each enantiomer

Question 19

Why do carboxylic acids have high boiling points

Answer 19

They exhibit all 3 intermolecular forces

They can dimerise- meaning that they double the size if the molecule therefore increasing London forces between itself and neighbour

Question 20

Solubility of carboxylic acids

Answer 20

Small carboxylic acids have the ability to hydrogen bond with water

Increase in mass= decrease in solubility

Solubility of carboxylic acids decreases as length of carbon chain increases. As hydrocarbon chains cannot form H bonds with water

Question 21

Why are optical isomers optically active

Answer 21

Because they can rotate the plane of polarisation of plane polarised light