JEE Main · 2019 · 09 Apr 2019 · Shift 1 · Hydrocarbons

The ring reacts faster in electrophilic substitution as its substituent pushes more electron density in. Benzonitrile's $-\mathrm{CN}$ drains density out strongly by both induction and resonance, so it is the most deactivated. Chlorobenzene's $-\text{Cl}$ withdraws on balance but only weakly. Toluene's $-\mathrm{CH}{}_3$ donates weakly, and anisole's $-\mathrm{OCH}{}_3$ donates strongly by resonance. Ranking from least to most reactive gives benzonitrile $<$ chlorobenzene $<$ toluene $<$ anisole.