Question

Benzaldehyde undergoes ___________ reaction due to __________ of $\alpha$-hydrogen atom.

• A. Cannizzaro' presence
• B. Cannizzaro; absence
• C. Henry's; absence
• D. Henry's; presence

Answer 1

The correct option is B Cannizzaro; absence

Benzaldehyde undergoes Cannizzaro reaction due to absence of $\alpha$ -hydrogen atom. One molecule of benzoic acid is oxidised to benzoate ion and other molecule is reduced to benzyl alcohol.
$2Ph-CHO\stackrel{KOH}{\to }PhCO{O}^{-}+PhC{H}_2-OH$