a
Aldehydes which do not have any a-hydrogen atom when heated with a concentrated solution of NaOH undergo a simultaneous oxidation and reduction (disproportionation) forming a salt of carboxylic acid and alcohol. This reaction is called Cannizaro reaction.
\(2 C_{6} H_{5} C H O+N A O H \longrightarrow\) \(C_{6} H_{5} C H_{2} O H(Benzylaloohol) +C_{6} H_{5} C O O N a (Sodium\; benzoate)\)