6.1.2: Carbonyl compounds

Question 1

What is the carbonyl functional group ?

Answer 1

C=O

Question 2

What reagents are used for the oxidation of aldehydes and what product is formed?

Answer 2

K2Cr2O7/H2SO4
Carboxylic acids

Question 3

What type of reactions do carbonyls undergo ?

Answer 3

Nucleophilic addition

Question 4

Give features of the reaction of carbonyls to form alcohols

Answer 4

• NaBH4
• Reduction reaction so represent with [H+]
• H- nucleophile from H20
• Protonation from H20
• Form OH- ion product and alcohol

Question 5

Give features of the reaction of carbonyls to form hydroxynitriles

Answer 5

• HCN
• Reduction reaction [H]
• CN- ion
• Protonation from H+, H20 or alcohol

Question 6

What is used to test for aldehydes and ketones ?

Answer 6

Brady’s reagent which forms an orange precipitate

Question 7

What is used to test for aldehydes only ?

Answer 7

Tollens reagent and heat which forms a silver mirror (oxidation to carboxylic acid)

Question 8

Give the method of idetification of substances after Bradys reagent

Answer 8

• Filter off orange precipitate
• Recrystalise to purify
• Obtain melting point
• Compare to literature values in database