(N/A) The Cannizzaro reaction is a chemical reaction in which two molecules of an aldehyde that lack $\alpha-$hydrogen atoms are heated with a strong base. This process involves self-oxidation and reduction (disproportionation),where one molecule is reduced to an alcohol and another is oxidized to a salt of a carboxylic acid.
$(a)$ Cannizzaro reaction of formaldehyde:
Two molecules of formaldehyde $(HCHO)$ react with concentrated $KOH$ upon heating to produce methanol $(CH_3OH)$ and potassium formate $(HCOOK)$.
$(b)$ Cannizzaro reaction of benzaldehyde:
Benzaldehyde lacks $\alpha-$hydrogen. When heated with concentrated $NaOH$,it undergoes the Cannizzaro reaction,where one molecule of benzaldehyde is reduced to benzyl alcohol $(C_6H_5CH_2OH)$ and another is oxidized to sodium benzoate $(C_6H_5COONa)$.