Clemmensen reduction of a ketone is carried out in the presence of which of the following?
- Glycol with KOH
- Zn-Hg with HCl
- LiAlH4
- H2 and Pt as catalyst
Answer
(2) Zn-Hg with HCl
Solution
As per NCERT, the carbonyl group of aldehydes and ketones is reduced to a CH2 group on treatment with zinc amalgam and concentrated hydrochloric acid (Clemmensen reduction).
>C=O Zn-Hg/HCl >CH2 + H2O
(1) Hydrazine followed by KOH in ethylene glycol is the Wolff–Kishner reduction; (3) LiAlH4 and (4) H2/Pt reduce a ketone to a 2° alcohol.
Answer: (2)