Question

The presence of nitro group (−NO₂) at o/p positions increases the reactivity of haloarenes towards nucleophilic substitution reactions.

Answer 1

The presence of nitro groups (−NO₂) at o/p positions increases the reactivity of haloarenes towards nucleophilic substitution reactions because nitro groups (−NO₂) at o/p positions withdraw the electron density from the benzene ring facilitating the attack of the nucleophile. The  negative charge in the carbanion formed, at ortho and para positions with respect to halogen atom, is stabilised through resonance and the presence of nitro groups (−NO₂), respectively.