Question

$1^{\circ },2^{\circ },\text{and}{3}^{\circ }$ amines can be best distinguished by:

• A. Hinsberg's reagent
  
• B. Tollen's reagent
• C. Fehling solution
• D. Carbylamine reaction

Answer 1

The correct option is A Hinsberg's reagent


Primary and secondary amines react with Hinsberg reagent. Further, only primary amines then react with alkali and dissolves in it becuase of presence of one acidic hydrogen on the nitrogen atom.
The primary amine forms sulphonamide which is soluble in alkali.

Secondary amine reacts with benzenesulphonyl chloride forming N, N-dialkyl benzenesulphonyl chloride forming N, N-dialkyl benzenesulphonamide, which is insoluble in alkali.
Tertiary amine does not react at all with the reagent. So it is the best reagent to distinguish all the three types of amines.
Hence, (a) is the correct option.