Question

Reaction of a carbonyl compound with one of the following reagents involves nucleophilic addition followed by elimination of water. The reagent is:

• A. a Girgnard reagent
• B. hydrazine in presence of feebly acidic solution
• C. sodium hydrogen sulphite
• D. hydrocyanic acid

Answer 1

The correct option is B hydrazine in presence of feebly acidic solution

Hydrocyanic acid or HCN has cyanide ion as a nucleophile. It can attack the carbonyl group of carbon and form cyanohydrins. The cyanohydrins are stable enough that they do not lose a molecule of water.

Sodium hydrogen sulphite or $NaHS{O}_3$ is an ionic compound and does not give any nucleophilic addition reaction with carbonyl groups.

Grignard reagent can attack the carbonyl group of the carbon via a nucleophile but the reaction does not involve loss of water molecule.

Reaction of carbonyl compounds with ammonia derivatives is an example of Nucleophilic addition elimination reaction.


Hence, option (c) is correct.