Q.Acetophenone ($\text{C}_6\text{H}_5\text{COCH}_3$) is to be reduced completely to ethylbenzene. Name the two classical methods that can achieve this (Clemmensen and Wolff-Kishner reduction), and state one condition (acidic or basic) under which each is carried out.

In the Clemmensen reduction, acetophenone is treated with zinc amalgam and concentrated hydrochloric acid; this proceeds under strongly ACIDIC conditions and removes the carbonyl oxygen entirely, converting $\text{C}_6\text{H}_5\text{COCH}_3$ directly to $\text{C}_6\text{H}_5\text{CH}_2\text{CH}_3$ (ethylbenzene). In the Wolff-Kishner reduction, acetophenone is first condensed with hydrazine, $\text{NH}_2\text{NH}_2$, to form the corresponding hydrazone, which is then heated strongly with a base such as $\text{KOH}$ (traditionally in ethylene glycol); this proceeds under strongly BASIC conditions, driving off nitrogen gas and again leaving ethylbenzene as the product. The two methods give the identical end product but proceed under essentially opposite pH conditions, …

Name the two classical carbonyl-to-methylene reductions and their opposite pH regimes (Clemmensen = acidic; Wolff-Kishner = basic); the choice between them in a real sy …

Mixing up which method uses acid and which uses base -- Clemmensen is the ACIDIC one (Zn-Hg + conc. HCl), Wolff-Kishner is the BASIC one (hydrazine …