(a) What is Cannizaro's reaction ? Write its mechanism.
(b) Discuss the structure of carbonyl group.

Explanation

(a) Cannizaro.s reaction : This reaction is shown by aldehydes having no `alpha`-H-atom. When such an aldehyde is treated with 50% of NaOH or KOH, it undergoes disproportionation to give an acid and an alcohol. This reaction is called Cannizaro.s reaction.
`underset("Benzaldehyde")(2C_(6)H_(5)CHO)underset((50%))(NaOH)_((aq)) to underset("Benzyl alcohol")(C_(6)H_(5)CH_(2)OH)+underset("Sodium benzoate")(C_(6)H_(5)COONa)`
Mechanism : It involves the following mechanism