Question

(a) For which group identification Tollen’s test is used. Give chemical equation.
(b) Give one difference between Clemmensen and Wolf-Kishner reduction.

Answer 1

a) For the identification of aldehyde and ketone group this reagent is used. Ketone does not give this tollen’s test because ammonical silver nitrate (Ag2O) (tollen’s reagent) is a mild oxidizing agent so it can’t oxidize ketone into carboxylic acid.
Reaction
Aldehyde+Ag2O——->Carboxylic acid+Silver mirror.
Silver mirror is the indication of presence of aldehyde group.

B) In both these reactions alkane is formed but the product formed in wolf kishner is better because in clemmensen alcohol is formed in between which reacts with concentrated HCl used in clemmensen reaction and degrade the product and hence product of wolf kishner is better.