Chapter 26

Question 1

What are aldehydes oxidised to?

Answer 1

Carboxylic acids

Question 2

How are aldehydes oxidised?

Answer 2

Using dichromate ions under reflux

Question 3

What are the observations for the oxidation of aldehydes?

Answer 3

Orange dichromate ions turn green

Question 4

What can aldehydes and ketones both be reduced to?

Answer 4

Alcohols

Question 5

What are aldehydes reduced to?

Answer 5

Primary alconois

Question 6

What are ketones reduced to?

Answer 6

Secondary alcohols

Question 7

What nucleophiles are used in nucleophilic addition?

Answer 7

NABH4 and HCN

Question 8

What is used to generate HCN in the lab?

Answer 8

Sodium cyanide and sulphuric acid

Question 9

How do you test for the presence of the carbonyl functional group?

Answer 9

Use brady’s reagent a yellow - orange precipitate will form

Question 10

How do you determine the identity of the aldehyde or the ketone?

Answer 10

Recrystalize then melt and compare the melting point to known values

Question 11

How do you distinguish between aldehydes and ketones?

Answer 11

Tollen’s reagent is used.
If an aldehyde is present, a silver mirror Will form
The aldehyde is oxidised

Question 12

What is a carboxylic acid?

Answer 12

Contain functional group COOH
Called carbonyl group

Question 13

How do you name a carboxylic acid?

Answer 13

The suffix -oic acid is added to the end of The longest carbon chain

Question 14

Explain the solubility of carboxylic acids

Answer 14

They Can contain more than one OH . group which means they can form hydrogen bonds to themselves or water molecules

Question 15

What happens to the solubility of the carboxylic acid as the non polar R group increases?

Answer 15

As the length of the chain increases, the solubility decreases

Question 16

What type of acid are carboxylic acids classed as?

Answer 16

Weak acids

Question 17

What is a carboxylic derivative acid?

Answer 17

Compounds that can be hydrolysed to form the parent carboxylic acid

Question 18

What are some examples of carboxylic acid derivatives ?

Answer 18

Esters
Acyl chlorides
Acid anhydrides
Amides

Question 19

How do you name an acyl chloride ?

Answer 19

After the parent carboxylic acid with the suffix -oyl chloride

Question 20

How can an acyl chloride be prepared from a carboxylic acid?

Answer 20

A reaction with the parent carboxylic acid and SOCl2
Thionyl chloride

Question 21

Explain the reactions of acyl chlorides

Answer 21

Very reactive
Can easily be converted into amines and esters
Can react with nucleophiles

Question 22

What is a condensation reaction?

Answer 22

Two molecules react together to form a larger molecule with the elimination of a small molecule

Question 23

What forms when you react an acyl chloride with an alcohol?

Answer 23

An ester

Question 24

What forms when you react an acyl chloride with water?

Answer 24

Carboxylic acids
This reaction happens very violently which means that the reactions must be carried out without the presence of water

Question 25

What forms when you react an acyl chloride with ammonia and amines?

Answer 25

Amides The ammonia and amines can act as nucleophiles by donating the lone pair of electrons on the nitrogen

Question 26

How is an acid anhydride formed?

Answer 26

The loss of water between two molecules of carboxylic acid

Question 27

Explain the reactivity of acid anhydrides

Answer 27

They react in a similar way to acyl chlorides but they less reactive making them safer.

Question 28

What is an ester?

Answer 28

They are carboxylic acid derivatives Contain -COO functional group OH replanted by an R group

Question 29

How do you name an ester?

Answer 29

After the parent carboxylic acid with the suffix -oate The alkyl group attached to the COO group is added as a prefix

Question 30

What is an esterification reaction?

Answer 30

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

Question 31

How can esters be made?

Answer 31

Reacting alcohols with acyl chlorides or acid anhydrides

Question 32

How do you make a phenyl ester?

Answer 32

By reacting the benzene containing compound with acyl chlorides or acid anhydrides

Question 33

What is acid hydrolysis?

Answer 33

The ester is heated under reflux with an acidic catalyst It will form an alcohol and a carboxylic acid

Question 34

What is alkaline hydrolysis?

Answer 34

Also known as saponification The ester is heated under reflux with an alkaline catalyst Forms a carboxylate ion and an alcohol