Which of the following carbonyl compounds is the most reactive towards nucleophilic addition of HCN?

A $C X_{6} H X_{5} - CO - C X_{6} H X_{5}$
B $CH X_{3} - CO - CH X_{3}$
C $CH X_{3} - CHO$
D $HCHO$

Answer: D

Reactivity falls with increasing alkyl or aryl substitution on the carbonyl carbon (less +I and less steric hindrance in the sp3 product). Formaldehyde has two hydrogens on the carbonyl carbon, so it is the most reactive.

Practice Organic Reaction Mechanisms I: Nucleophiles and Carbonyl Addition More on Nucleophilic addition to aldehydes and ketones

Previous questionNext question

Which of the following carbonyl compounds is the most reactive towards nucleophilic addition of HCN?

Answer: D

More questions on Nucleophilic addition to aldehydes and ketones