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 Grignard reagent
(b) hydrazine in presence of feebly acidic solution
(c) hydrocyanic acid
(d) sodium hydrogen sulphite

Answer 1

Answer:

Sodium hydrogen sulphite

Answer 2

Answer:

(b) hydrazine in presence of feebly acidic solution

Explanation:

The reaction of carbonyl compounds with ammonia derivatives give the additional product followed by the elimination reaction. Thus, the slightly acidic medium generates a nucleophilic centre for the attack of weak base like ammonia derivatives.

The product formation is favoured due to therapid dehydration of the intermediate to form -C = NG.  

The carbonyl compounds react with ammonia derivatives in weakly acidic medium as follows -  

- OH, -NH2, -NHC6H5, - NHCONH2 etc

Thus, the reagent formed will be hydrazine in presence of feebly acidic solution.