Question

Give chemical tests to distinguish between the following pairs: (i) Propanal and Propanone

Hint:

Aldehydes respond to Tollen’s/Fehling’s; acids react with NaHCO\(_3\). Use simple visible tests for easy differentiation.

Answer 1

(i) **Test:** Tollen’s Test or Fehling’s Test
- Propanal (aldehyde) gives positive test → forms silver mirror (Tollen’s) or red ppt (Fehling’s). - Propanone (ketone) gives negative test. \[ \boxed{\text{Tollen’s/Fehling’s test distinguishes aldehydes from ketones}} \] (ii) Benzaldehyde and Benzoic acid
Solution:
(ii) **Test:** Sodium bicarbonate (NaHCO\(_3\)) test
- Benzoic acid reacts with NaHCO\(_3\) → brisk effervescence (CO\(_2\))
- Benzaldehyde shows no reaction \[ \boxed{\text{NaHCO}_3\ \text{test distinguishes acids from aldehydes}} \]