Question

The correct order of acid strengths of benzoic acid $(X)$, peroxybenzoic acid $(Y)$ and $p$-nitrobenzoic acid $(Z)$ is

• A. $Y>Z>X$
• B. $Z>Y>X$
• C. $Z>X>Y$
• D. $Y>X>Z$

Answer 1

Answer: (C)

$\because$ In $p$-nitrobenzoic acid $(Z)-N{O}_2$ present as electron withdrawing group, thus is most acidic

$(X)\because$ Benzoic acid is stabilised via resonance, thus is more acidic than per oxybenzoic acid.

$(Y)$ peroxy benzoic acid does not show any such resonance.

Thus is least acidic.
Hence, correct order is $Z>X>Y$.