question_answer

The most reactive compound towards formation of cyanohydrin on treatment with HCN followed by acidification is

A)  benzaldehyde

B)  p-nitrobenzaldehyde                 

C)  phenylacetaldehyde

D)  p-hydroxybenzaldehyde

Correct Answer: B

Solution :

 Addition of HCN to a carbonyl compound is a nucleophilic addition reaction. \[-\text{N}{{\text{O}}_{\text{2}}}\]group being electron withdrawing increases the polarity (or electron deficiency) of catbonyl carbon and thus, makes the  group of benzaldehyde more reactive towards HCN. 34.