In the presence of concentrated aqueous or alcoholic alkali, aldehydes which do not have α – hydrogen atom under go self oxidation and reduction (disproportionation) to give a mixture of alcohol and a salt of carboxylic acid. This reaction is called Cannizaro reaction.
Benzaldehyde on treatment with concentrated NaOH (50%) gives benzyl alcohol and sodium benzoate.
This reaction is an example of disproportion reaction.
