Question

Out of (ref. image), which one is more reactive towards nucleophilic substitution reaction and why?

Answer 1

More reactive towards nucleophilic substances reaction.

So, nucleophilic substances means, nucleophilic is attacking and benzene act as electrophile, so as we know, more electron withdrawing group present on benzene more electrophilic the benzene ring.

So, in B we have $N{O}_2$ group attached to ring so, $N{O}_2$ is strong electron withdrawing group so, it make benzene more electrophilic as it pulls electron density towards it self. So more reactive towards nucleophilic substances.