Aldehydes that lack an $\alpha$-hydrogen atom cannot form enolates and thus cannot undergo Aldol condensation. Instead, in the presence of concentrated alkali ($50\%NaOH$), they undergo the Cannizzaro Reaction.

• Nature: It is a Self-Redox (Disproportionation) reaction.
• Process: One molecule is reduced to an alcohol, while another molecule is oxidized to the salt of a carboxylic acid.
• Examples: Formaldehyde ($HCHO$) and Benzaldehyde ($C_6{H}_{5}CHO$).