See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

Concept: Friedel-Crafts reactions (alkylation and acylation) are electrophilic aromatic substitution reactions that require a Lewis acid catalyst, typically AlCl3. Step 1 - Role of AlCl3: AlCl3 is a strong Lewis acid (electron pair acceptor). In a Friedel-Crafts alkylation, AlCl3 reacts with an alkyl halide (e.g., RCl) by accepting a lone pair from the chlorine atom, forming a complex that facilitates the generation of a carbocation (R+) or a highly polarized species acting as an electrophile: RCl + AlCl3 → R+ [AlCl4]- (or a polarized R---Cl---AlCl3 complex). Step 2 - The electrophile attacks benzene: This carbocation (R+) or the polarized complex serves as the electrophile that attacks the pi electron system of the benzene ring, initiating electrophilic aromatic substitution. Step 3 - Why other options fail: (a) 'To absorb HCl' - AlCl3 does not primarily function as an HCl absorber; HCl is released as a byproduct but that is not the role of AlCl3. (b) 'To release HCl' - AlCl3 does not release HCl; rather HCl is a byproduct of the overall reaction regenerating AlCl3. (d) 'To produce nucleophile' - AlCl3 produces an electrophile (carbocation or acylium ion), not a nucleophile. Benzene itself acts as the nucleophile. Therefore, the correct answer is C.