2,4-Dinitrophenyl-
2,4 Dinitrophenyl-
Semicarbazide
Semicarbazone
2 Reduction
(i) Reduction to alcohols: Aldehydes and ketones are reduced to
primary and secondary alcohols respectively by sodium
borohydride (NaBH4) or lithium aluminium hydride (LiAlH4) as
well as by catalytic hydrogenation (Unit 7, Class XII) (ii) Reduction to hydrocarbons: The carbonyl group of aldehydes
and ketones is reduced to CH2 group on treatment with zinc-
amalgam and concentrated hydrochloric acid [Clemmensen
hydrazone
hydrazine
Rationalised 2023-24
239
Aldehydes, Ketones and Carboxylic Acids
reduction] or with hydrazine followed by heating with sodium
or  potassium hydroxide in high boiling solvent such as ethylene
glycol (Wolff-Kishner reduction) 3