Identify the reaction so that carbonyl group of aldehydes and ketones is reduced to methylene group on…

Identify the reaction so that carbonyl group of aldehydes and ketones is reduced to methylene group on treatment with Zinc-amalgam and concentrated hydrochloric acid.
  1. Wolf-Kishner reduction.
  2. Stephan reaction.
  3. Clemmensen reduction.
  4. Etard reaction.

Solution

The reaction characterized by reduction of a carbonyl group to a methylene group using zinc–amalgam and concentrated $\mathrm{HCl}$ is known as the Clemmensen reduction.

In comparison, the Wolf–Kishner reduction employs hydrazine and a strong base such as $\mathrm{KOH}$ or $\mathrm{NaOH}\;$, the Stephan reaction converts nitriles to aldehydes using stannous chloride and hydrochloric acid followed by hydrolysis, while the Étard reaction oxidizes a methyl group attached to an aromatic ring to an aldehyde using chromyl chloride.

The correct answer is $\boxed{C}$.

Asked in: MHT CET 2025 (05 May Shift 2)

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