The Clemmensen Reduction is used to reduce the carbonyl group ($C=O$) of aldehydes and ketones directly into a methylene group ($-C{H}_2-$).

• Reagents: Zinc Amalgam ($Zn-Hg$) and concentrated Hydrochloric acid ($HCl$).
• Application: It is highly effective for converting aromatic ketones to alkylbenzenes.
• Note: Because it uses concentrated acid, it is not suitable for substrates containing acid-sensitive groups. In such cases, the basic Wolff-Kishner reduction is used instead.