CH3CHO →Δdil. NaOH X. X is
CH3 – CH = CH – CHO
(CH3)2CH – CH2 – CHO
CH2 = CH – CH2 – CHO
Carbonyl compounds containing α-hydrogen atoms undergo condensation in presence of dil.alkali to form β-hydroxy carbonyl compound Aldol (or) ketol.
Aldol (or ketol) on heating gives α, β-unsaturated carbonyl compound.