See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

Step 1 - Concept: The rate of electrophilic aromatic substitution (EAS) depends on the electron density of the aromatic ring. Electron-donating groups (EDGs) increase the ring's electron density and accelerate EAS, while electron-withdrawing groups (EWGs) decrease electron density and retard EAS. Step 2 - Classify each substituent: - (a) Nitrobenzene: NO2 is a strong electron-withdrawing group (both by induction and resonance). It strongly deactivates the ring. This gives the slowest rate among the four. - (b) Chlorobenzene: Cl is a weak deactivator overall (withdraws by induction, donates by resonance, net deactivating). The ring is slightly less reactive than benzene. - (c) Toluene: CH3 is an electron-donating group (hyperconjugation and induction). It activates the ring, making it more reactive than benzene. - (d) Benzene: No substituent, baseline reactivity. Step 3 - Order of reactivity: - Toluene (c): most reactive (activated ring) - Benzene (d): baseline - Chlorobenzene (b): slightly deactivated (less reactive than benzene) - Nitrobenzene (a): strongly deactivated (least reactive) This gives: c > d > b > a Step 4 - Why other options fail: - Option (a) c > b > a > d: places benzene last, incorrect since NO2 deactivates more than Cl. - Option (b) c > d > a > b: places nitrobenzene above chlorobenzene, incorrect since NO2 is a stronger deactivator than Cl. - Option (c) a > b > c > d: completely reversed, placing the most deactivated compound first. Therefore, the correct answer is D.