Question

Aromatic aldehydes are less reactive towards nucleophilic addition reaction.
v) Aldol condensation cannot take place in the absence of α-hydrogen

Answer 1

Aromatic aldehydes are less reactive towards nucleophilic addition reaction because aromatic ring pulls electron density.

Aldol condensation cannot take place in the absence of α-hydrogen because in the first step aldehyde must tautomerize to enol form, and it is impossible without α-hydrogen.