Question

A carbonyl compound reacts with hydrogen cyanide to form cyanohydrin which on hydrolysis forms a racemic mixture of $\alpha$ -hydroxy acid. The carbonyl compound is:

• A. diethyl ketone
• B. formaldehyde
• C. acetaldehyde
• D. acetone

Answer 1

Answer: (C)

acetaldehyde

Acetaldehyde reacts with hydrogen cyanide $\left(HCN\right)$ to form cyanohydrin $\left(C{H}_{3}CH\right(OH\left)CN\right)$ which on hydrolysis forms a racemic mixture of $\alpha -$ hydroxy acid $\left(C{H}_{3}CH\right(OH\left)COOH\right)$

As the cyanohydrin of acetaldehyde contains chiral centre so we will get racemic mixture.

Hence the correct answer is option C.