Why is nitrobenzene a meta-directing group?

Nitrobenzene is a meta-directing compound because the nitro group (–NO₂) withdraws electron density from the benzene ring and makes the ortho and para positions less favourable for substitution. As a result, incoming electrophiles mainly attach at the meta position during electrophilic aromatic substitution reactions.

The –NO₂ group is a strong electron-withdrawing group due to its negative inductive effect (–I effect) and negative resonance effect (–R effect). These effects reduce the electron density of the aromatic ring, especially at the ortho and para positions, making them less reactive.

The meta position becomes comparatively more favourable because the intermediate formed during meta substitution is more stable than those formed during ortho or para substitution.

This behaviour of nitrobenzene helps students understand directing effects, aromatic reactions, and how functional groups influence chemical reactivity in organic chemistry.