Question

Cannizaro’s reaction is an example of auto oxidation.
A. It is a typical reaction of aliphatic aldehyde
B. It is a reaction answered by all aldehyde
C. It is a reaction answered by only aldehydes which do not contains \[\alpha \] hydrogen
D. It is a reaction answered only by aromatic aldehydes.

Answer 1

Hint:In Cannizaro’s reaction, two molecules of aldehyde on reacting with base undergo disproportionation reaction to give one molecule of carboxylic acid and one molecule of alcohol.

Complete step by step answer:
The auto-oxidation is the reaction where the oxidation reaction takes place due to the presence of oxygen.
Cannizaro’s reaction is a base induced disproportionation reaction, which is named after Stanislao Cannizaro. In this reaction two non-enolizable aldehydes undergo redox disproportionation is the presence of base to give carboxylic acid and primary aldehyde.
The difference between the Aldol condensation reaction and Cannizaro’s reaction is that the in aldol condensation presence of \[\alpha \]-hydrogen is must and in Cannizaro’s reaction, \[\alpha \]-hydrogen is not present.
The Cannizaro’s reaction is seen in both aliphatic aldehyde and aromatic aldehyde but only in aldehydes and no other functional group containing compounds.
In Cannizaro’s reaction, redox reaction takes place as one molecule of aldehyde is oxidized to carboxylic acid and another molecule is reduced to primary alcohol.
Thus, Cannizaro’s reaction is an example of auto oxidation answered by only aldehydes which do not contains \[\alpha \] hydrogen
Therefore, the correct option is C.

Note:
In crossed Cannizaro’s reaction, formaldehyde is used as the reducing agent and as a result formic acid is formed. In cross Cannizaro’s reaction two different aldehydes are taken.