Question

Identify the end product [C] in the following sequence of chemical reaction:

\[\ce{CH ≡ CH ->[dil{.} H2SO4/HgSO4][][A]->[{[O]}][][B]->[PCl5][][C]}\]

Options

• Acetic anhydride

• Acetic acid

• Acetyl chloride

• Ethyl chloride

Answer 1

Acetyl chloride

Explanation:

\[\ce{CH ≡ CH ->[dil. H2SO4/HgSO4][]\underset{[A]}{CH3CHO}->[{[O]}][]\underset{[B]}{CH3COOH}->[PCl5][]\underset{[C]}{CH3COCl}}\]

1. The hydration of ethyne (CH = CH) using dilute H₂SO₄ and HgSO₄ produces ethanal (acetaldehyde).
2. Subsequent oxidation of ethanal yields acetic acid as the next intermediate product.
3. Treatment of acetic acid with PCl₅ converts the carboxyl group (−COOH) into an acid chloride group (−COCl).
4. This final reaction yields acetyl chloride as the end product.