Carboxylic Acid Derivatives

Question 1

What do ammonia and amines act as in reactions with acyl chlorides?

Answer 1

Nucleophiles

They donate a pair of electrons from the nitrogen atom to an electron-deficient species.

Question 2

What is formed when ammonia reacts with acyl chlorides?

Answer 2

Primary amide

The nitrogen atom in a primary amide is attached to one carbon atom.

Question 3

What is the reaction product of ethanoyl chloride and ammonia?

Answer 3

Ethanamide and ammonium chloride

Question 4

What type of amide is formed when a primary amine reacts with an acyl chloride?

Answer 4

Secondary amide

The nitrogen atom in a secondary amide is attached to two carbon atoms.

Question 5

What is the name of the secondary amide formed from methylamine and ethanoyl chloride?

Answer 5

N-methylethanamide

Question 6

How do acid anhydrides react compared to acyl chlorides?

Answer 6

They react in a similar way but are less reactive

Useful for laboratory preparations where acyl chlorides may be too reactive.

Question 7

What is the equation for the formation of phenyl ethanoate from ethanoic anhydride and phenol?

Answer 7

2(CH3CO)2O + C6H5OH → CH3COOC6H5 + CH3COOH

Question 8

What are the two steps in the mechanism of acyl chloride reactions with nucleophiles?

Answer 8

Addition followed by elimination

Question 9

What is the product when acyl chlorides react with alcohols?

Answer 9

Esters

Question 10

What is formed when acyl chlorides react with water?

Answer 10

Carboxylic acids

This reaction produces dense steamy hydrogen chloride fumes.

Question 11

What is the process of hydrolysis of esters?

Answer 11

Chemical breakdown of a compound in the presence of water or in aqueous solution.

Question 12

What is required for acid hydrolysis of an ester?

Answer 12

Heating under reflux with dilute aqueous acid

Question 13

What is the product of the acid hydrolysis of an ester?

Answer 13

Carboxylic acid and an alcohol

Question 14

What is alkaline hydrolysis also known as?

Answer 14

Saponification

Question 15

What does alkaline hydrolysis of an ester produce?

Answer 15

Carboxylate ion and an alcohol

Question 16

How can acyl chlorides be prepared?

Answer 16

By reaction with thionyl chloride (SOCl2)

The other products, SO2 and HCl, are evolved as gases.

Question 17

What is the reaction for the formation of propanoyl chloride from propanoic acid?

Answer 17

Propanoic acid + SOCl2 → Propanoyl chloride + SO2 + HCl

Question 18

What is esterification?

Answer 18

The reaction of an alcohol with a carboxylic acid to form an ester

Question 19

What acts as a catalyst in the esterification process?

Answer 19

Concentrated sulfuric acid

Question 20

What is the molecular formula for ethyl propanoate?

Answer 20

C5H10O2

Question 21

What is a characteristic smell of many esters?

Answer 21

Fruity smell

Question 22

What is the first step in making ethyl propanoate in the laboratory?

Answer 22

Mix ethanol with propanoic acid and concentrated sulfuric acid

Question 23

What is the purpose of adding aqueous sodium carbonate after the ester formation?

Answer 23

To neutralize acids in the mixture

Question 24

What do ammonia and amines act as in reactions with acyl chlorides?

Answer 24

Nucleophiles

They donate a pair of electrons on the nitrogen atom to an electron-deficient species.

Question 25

What type of amide is formed when ammonia reacts with acyl chlorides?

Answer 25

Primary amide ## Footnote In a primary amide, the nitrogen atom is attached to one carbon atom.

Question 26

What is the reaction product of ethanoyl chloride and ammonia?

Answer 26

Ethanamide and ammonium chloride ## Footnote The reaction shows ammonia converting ethanoyl chloride into a primary amide.

Question 27

What type of amide is formed when a primary amine reacts with an acyl chloride?

Answer 27

Secondary amide ## Footnote In a secondary amide, the nitrogen atom is attached to two carbon atoms.

Question 28

What is the name of the secondary amide formed from the reaction of ethanoyl chloride and methylamine?

Answer 28

N-methylethanamide ## Footnote This indicates that the methyl group is attached to the nitrogen atom.

Question 29

How do acid anhydrides react compared to acyl chlorides?

Answer 29

They react in a similar way but are less reactive ## Footnote Useful for laboratory preparations where acyl chlorides may be too reactive.

Question 30

What is the reaction equation for the formation of phenyl ethanoate from ethanoic anhydride and phenol?

Answer 30

2(CH3CO)2O + C6H5OH → CH3COOC6H5 + CH3COOH ## Footnote This shows the conversion of ethanoic anhydride and phenol into phenyl ethanoate and ethanoic acid.

Question 31

What are the two steps in the mechanism of acyl chloride reactions with nucleophiles?

Answer 31

Addition and elimination ## Footnote This mechanism shows how nucleophiles interact with acyl chlorides.

Question 32

What happens in the addition step of the nucleophilic addition-elimination mechanism?

Answer 32

The nucleophile donates a lone pair to the carbon atom in the C=O group ## Footnote A dative covalent bond is formed, leading to a negatively charged intermediate.

Question 33

What occurs during the elimination step of the nucleophilic addition-elimination mechanism?

Answer 33

The C=O double bond is reformed, and a chloride ion is removed ## Footnote A proton is also lost to complete the elimination.

Question 34

True or False: Acyl chlorides undergo substitution reactions with nucleophiles.

Answer 34

False ## Footnote Acyl chlorides undergo nucleophilic addition-elimination, which is different from substitution.