Question

What is the action of nirtomethane on benzaldehyde in presence of ethanolic potassium hydroxide ?

Answer 1

$\textbf{Aldol type condensations}$: Owing to the presence of active α-hydrogen atoms, primary and secondary nitro - compounds undergo condensation with aldehydes ; this is similar to Aldol
condensation.
The α-carbanion is formed from the nitro alkanes (having α- hydrogen atom),
which attack as a nucleophile to the carbonyl carbon atom of aldehydes.

e.g.,. Nitromethane condenses with benzaldehyde in the presence of ethanolic potassium hydroxide to form $\omega\textbf{-nitrostyrene}$ and water.
reaction is ..
CH3-NO2 + C6H5-CHO ---> C6H5-CH=CH-NO2 + H2O