Question

Equal amount of aqueous solution of CuSO4 and alkaline sodium potassium tartrate is mixed and treated with aliphatic aldehyde

• A. There will be no reaction
• B. Red brown ppt of CuO is formed
• C. Red brown ppt of Cu₂O is formed
• D. Blue ppt of CuO is formed

Answer 1

Answer: (C)

Red brown ppt of Cu₂O is formed

Answer 2

Fehling's solution, containing $\text{Cu}^{2+}$ ions complexed with tartrate in an alkaline medium, reacts with aliphatic aldehydes. The aldehyde is oxidized to a carboxylate, while $\text{Cu}^{2+}$ ions are reduced to $\text{Cu}^{+}$ ions, which precipitate as red-brown copper(I) oxide ($\text{Cu}_2\text{O}$).