[3.3.8] Aldehydes & Ketones

Question 1

What is an aldehyde? How do you name it?

Answer 1

Question 2

Name this molecule.

Answer 2

Ethanal.

Question 3

What is an ketone? How do you name it?

Answer 3

Question 4

Name this molecule.

Answer 4

Propanone.

Question 5

What are carbonyls?

Answer 5

Question 6

Describe the intermolecular forces in carbonyls.

Answer 6

Question 7

Describe the solubility of carbonyls.

Answer 7

Question 8

Describe and explain the reaction of carbonyls.

Answer 8

Question 9

Describe the oxidation of primary, secondary and tertiary alcohols.

Answer 9

Question 10

What can aldehydes be oxidised to that ketones cannot be?

What reageants can be used and what are the conditions?

Answer 10

Question 11

Show the equation for the oxidation of propanal.

Answer 11

Question 12

Write the full equation for the oxidation of ethanal to ethanoic acid by potassium dichromate.

What will you observe?

Answer 12

Question 13

What are the functional group tests for aldehydes?

In each case: what reagent is used, what are the conditions, what is the reaction and what can you observe?

Answer 13

Question 14

What reageant and conditions are used to reduce carbonyls?

Answer 14

Question 15

What do aldehydes reduce to?

What do ketones reduce to?

What are these reduction reactions an example of?

Answer 15

• Aldehydes reduce to primary alcohols.
• Ketones reduce to secondary alcohols.
• These reduction reactions are examples of nucleophilic addition.

Question 16

Write overall equation for the reduction reaction of propanal using [H] as the reductant.

Name the product.

Answer 16

Question 17

Write overall equation for the reduction reaction of propanone using [H] as the reductant.

Name the product.

Answer 17

Question 18

Outline the nucleophilic addition mechanism for the reduction reaction of propanone with NaBH₄ (the nucleophile should be shown as H–).

Answer 18

Question 19

How else can carbonyls be reduced other than via NaBH₄?

What reagent is used and in what conditions?

Answer 19

Question 20

Write equations for the catalytic hydrogenation of ethanal and propanone.

Answer 20

Question 21

What reagent (and why), conditions and through what mechanism do carbonyls form hydroxynitriles?

Answer 21

Question 22

Write the overall equation between propanone and hydrogen cyanide.

Name the product and draw its displayed formula.

Answer 22

Question 23

Write the overall equation between ethanal and hydrogen cyanide.

Name the product and draw its displayed formula.

Answer 23

Question 24

Outline the nucleophilic addition mechanism for the reaction of propanone with KCN followed by dilute acid.

Answer 24

Question 25

What's the advantage of using KCN or NaCN than HCN?

Answer 25

Question 26

What is the hazard of using KCN?

Answer 26

**Toxic**.

Question 27

Explain why nucleophilic addition reactions of KCN, followed by dilute acid, can produce a mixture of enantiomers.

Answer 27