Question

By taking a suitable example give one laboratory test which is commonly used for the detection of aldehydes and ketones .write the names of two regents used for distinguishing between aldehydes and ketones

Answer 1

(i) Tollen's Test for Aldehydes

Tollen's reagent is a chemical reagent used to determine the presence of an aldehyde functional group. The reagent consists of a solution of silver nitrate and ammonia. A positive test with Tollen's reagent is indicated by the precipitation of elemental silver, often producing a characteristic "silver mirror" on the inner surface of the reaction vessel.

(ii) Jones (Chromic acid) Oxidation Test for Aldehydes

The Jones reagent is a mixture of chromic anhydride and dilute sulfuric acid (CrO₃ + H₂SO₄ + H₂O) in acetone. Aldehydes are oxidised to carboxylic acids and the solution turnes a green to blue in color .