Question

Arrange the following in increasing order of their reactivity for nucleophilic addition reaction:

• A. $a<b<c<d$
• B. $a<d<c<b$
• C. $c<b<a<d$
• D. $c<a<b<d$

Hint:

Electron withdrawing groups increase carbonyl reactivity; donating groups decrease it.

Answer 1

The Correct Option is A

The reactivity of carbonyl compounds towards nucleophilic addition depends on the electron withdrawing or donating nature of the substituents.
% Option (a) Benzophenone has two electron-donating phenyl groups — least reactive.
% Option (b) p-Methylbenzaldehyde — methyl is slightly donating.
% Option (c) Benzaldehyde — no additional substituent.
% Option (d) p-Nitrobenzaldehyde — nitro group is strongly withdrawing, making the carbon more electrophilic.
Thus, reactivity order: $a<b<c<d$