Reactions due to a-hydrogen
Acidity of aaaaa-hydrogens of aldehydes and ketones: The aldehydes
and ketones undergo a number of reactions due to the acidic nature
of a-hydrogen The acidity of a-hydrogen atoms of carbonyl compounds is due
to the strong electron withdrawing effect of the carbonyl group and
resonance stabilisation of the conjugate base (i) Aldol condensation:  Aldehydes and ketones having at least one
a-hydrogen undergo a reaction in the presence of dilute alkali
as catalyst to form b-hydroxy aldehydes (aldol) or b-hydroxy
ketones (ketol), respectively This is known as Aldol reaction