(a) Wolff-Kishner Reduction Reaction - In this reaction, the reduction of carbonyl compounds to hydrocarbons takes place by heating them with hydrazine and a base to form hydrazone which is further reduced to form methylene group along with nitrogen gas.

(b) Cannizzaro Reaction - The self-oxidation reduction (disproportionation) reaction of aldehydes having no α-hydrogens when reacts with concentrated alkali is known as the Cannizzaro reaction. In this reaction, two molecules of aldehydes react where one is reduced to alcohol and the other is oxidized to carboxylic acid.