The number of the correct reaction(s) among the following is _______.

Solution

Chemistry ma’am · 3 steps

For each reaction, ask what the reagent really makes, then compare it with the product drawn.

1. Method. Each reagent here is a named reaction with a fixed product. A reaction counts only if the product drawn is that product.

   Reaction	What the reagent does	Real product	Drawn product
   (A) C₆H₆ + C₆H₅COCl, anhyd. AlCl₃	Friedel–Crafts acylation adds C₆H₅CO⁻ and stops at the ketone	Benzophenone, C₆H₅COC₆H₅	Diphenylmethane, C₆H₅CH₂C₆H₅: wrong
   (B) C₆H₅COCl, H₂, Pd-BaSO₄	Rosenmund reduction turns -COCl into -CHO	Benzaldehyde, C₆H₅CHO	Benzoic acid, C₆H₅COOH: wrong
   (C) C₆H₆, CO + HCl, anhyd. AlCl₃/CuCl	Gattermann–Koch formylation puts -CHO on the ring	Benzaldehyde, C₆H₅CHO	Benzaldehyde: correct
   (D) C₆H₅CONH₂, H₃O⁺, heat	Acid hydrolysis of an amide breaks the C–N bond	Benzoic acid and NH₄⁺	Aniline, C₆H₅NH₂: wrong

2. Why D fails. Aniline needs the ring carbon to lose the C=O carbon. That happens in the Hofmann bromamide reaction (Br₂/NaOH), not in acid hydrolysis, which keeps the carbon and gives C₆H₅COOH.
3. So. Only reaction (C) shows the right product, so the number of correct reactions is 1.

The common slip: 2. Counting (A) as correct gives 2. AlCl₃ does not reduce the C=O to CH₂, so acylation stops at benzophenone.

The idea to keep. Learn each named reaction by its product: acylation stops at a ketone, Rosenmund stops at an aldehyde, Gattermann–Koch gives ArCHO, and amide hydrolysis gives the acid. Losing a carbon needs Hofmann.

Answer from the NTA final answer key. Solution by PrepWiser.