Q. A carbonyl compound reacts with hydrogen cyanide to form cyanohydrin which on hydrolysis forms a racemic mixture of α-hydroxy acid. The carbonyl compound is :
A) acetaldehyde
B) acetone
C) diethyl ketone
D) formaldehyde
Explanation
[Solution from source] Acetaldehyde adds HCN to give CH₃CH(OH)CN, whose central carbon has four different groups; attack from either face is equally likely, so a racemic cyanohydrin and, on hydrolysis, racemic lactic acid result. Formaldehyde, acetone and diethyl ketone give cyanohydrins with two identical groups, which are achiral. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.