Question

In normal reaction conditions, chlorobenzene does not react with NaOH, but 1-chloro-4-nitrobenzene reacts with NaOH in these conditions. Explain.

Answer 1

If we compare the structures of chloro-benzene and 1-chloro-4-nitrobenzene then in one structure there is presence of nitro group $(-NO_2)$ which is very strong electron withdrawing activates the ring for the nucleophilic attack

When the reaction with chloro-4-nitrobenzene occurs, SNAr mechanism takes place, because Meisenheimer's intermediate is stabilized by resonance