Identify the catalyst in Friedel-Crafts acylation reaction.

The correct answer is Option (4) → Anhydrous AlCl₃

NCERT (2026-27 edition):
8.2.3 Preparation of Ketones – “3. From benzene or substituted benzenes
When benzene or substituted benzene is treated with acid chloride in the presence of anhydrous aluminium chloride, it affords the corresponding ketone. This reaction is known as Friedel-Crafts acylation reaction.”

7.6.3 Chemical Reactions – “(ii) Friedel-Crafts reaction: Anisole undergoes Friedel-Crafts reaction, i.e., the alkyl and acyl groups are introduced at ortho and para positions by reaction with alkyl halide and acyl halide in the presence of anhydrous aluminium chloride (a Lewis acid) as catalyst.”