Question

Write a Fehling solution test for ethanal.

Answer 1

Take a small amount of ethanol \[\ce{CH3CHO}\] in a test tube. Add an equal amount of Fehling’s solution (a mixture of Fehling A and Fehling B). Heat the mixture gently.

Observation: A reddish-brown precipitate of cuprous oxide \[\ce{Cu2O}\]is formed. 

Chemical Reaction:

\[\ce{CH3CHO × 2Cu^2+ + 50H¯ -> CH3COO¯ + Cu2O ↓ + 3H2O}\]

Ethanol gives a positive Fehling test, confirming the presence of an aldehyde group.