Question

Does acetaldehyde undergo aldol condensation ?

Answer 1

An aldol condensation is a condensation reaction in organic chemistry in which an enol or an enolate ion reacts with a carbonyl compound to form a hydroxy aldehyde or hydroxy ketone, followed by dehydration to give a conjugated enone. In its usual form, it involves the nucleophilic addition of a ketone enolate to an aldehyde to form a β-hydroxy ketone, or "aldol" (aldehyde + alcohol),a structural unit found in many naturally occurring molecules and pharmaceuticals.

Complete answer:
Ethanal (common name acetaldehyde) is an organic chemical compound with the formula $CH3CHO$ , sometimes abbreviated by chemists as $MeCHO$ ( $Me$ = methyl). It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale in industry. Aldehydes having at least one $\alpha - H$ undergo Aldol condensation in the presence of a base to give $\alpha -$ hydroxy aldehydes (aldol). Since acetaldehyde $C{H_3}CHO$ has $\alpha - H$ whereas formaldehyde $HCHO$ has no $\alpha - H$ , therefore the former can undergo aldol condensation while later does not.

Note:
Aldehydes having at least one α−H undergo Aldol condensation in the presence of a base to give $\alpha -$ hydroxy aldehydes (aldol). Since acetaldehyde has carbon so it goes under aldol condensation.Aldol condensation is one of the organic chemistry reactions of carbon compounds , especially aldehydes and ketones on the condition that it must contain $\alpha - H$ or alpha hydrogen.