Question

Write Tollen’s reagent test for acetaldehyde.

Answer 1

Acetaldehyde, when warmed with Tollen’s reagent (ammoniacal silver nitrate), gives a silver mirror due to the formation of metallic silver.
Acetaldehyde is oxidized to ammonium acetate.

\[\ce{CH3CHO + 2[Ag(NH3)2]+ + 3OH- -> CH3COO- + 2Ag\downarrow + 4NH3 + 2H2O}\]

Formation of a silver mirror confirms the presence of an aldehyde group.