See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

Concept: Friedel-Crafts Alkylation requires an electron-rich aromatic ring. The nitro group (-NO2) is a strong electron-withdrawing group (EWG) that deactivates the benzene ring toward electrophilic aromatic substitution (EAS). Step 1: Identify the reaction type. The reagents are an arene (nitrobenzene, Ph-NO2), an alkyl halide (Et-Cl), and a Lewis acid catalyst (AlCl3). This is a Friedel-Crafts alkylation setup. Step 2: Assess ring reactivity. The nitro group (-NO2) is a powerful meta-director and strong deactivator. It withdraws electron density from the ring via both inductive and resonance effects, making the ring significantly electron-poor. Step 3: Determine feasibility. Friedel-Crafts reactions (both alkylation and acylation) do NOT proceed on benzene rings that carry strongly deactivating groups such as -NO2, -SO3H, -COOH, -CHO, -COR, or -CF3. The ring is too deactivated to attack the electrophile (ethyl carbocation or Et-AlCl3 complex). Additionally, AlCl3 coordinates strongly with the nitro group, further reducing availability of the catalyst. Step 4: Evaluate each option: - Option (a) Ph-NH-Et: This would require reduction of the nitro group to amine and then N-alkylation, which is not what these reagents do directly. - Option (b) no-reaction: Correct, because nitrobenzene is too deactivated for Friedel-Crafts alkylation to occur. - Option (c) ortho/meta-nitroethylbenzene: Would require successful EAS, which does not occur on deactivated rings. - Option (d) para-nitroethylbenzene: Same reasoning as (c); EAS cannot occur on the deactivated ring. Therefore, the correct answer is B.