Which of the following reagents reacts with acetone to yield a pure nucleophilic addition product without the subsequent elimination of a water molecule?

Step-by-step solution

Acetone undergoes nucleophilic addition with hydrogen cyanide ( HCN ) to form a cyanohydrin. This is a pure nucleophilic addition reaction where no elimination of water takes place. Reagents like 2,4-dinitrophenylhydrazine, hydroxylamine, and primary amines (such as p -toluidine) are ammonia derivatives ( NH ₂- Z ). They react with carbonyl compounds via a nucleophilic addition-elimination mechanism, where the initial addition is followed by the elimination of a water molecule to form a carbon-nitrogen double bond