Which among the following react with Hinsberg's reagent?
A.
B.
C.CH₃-NH₂
D. N(CH₃)₃
E.
Choose the correct answer from the options given below :

Solution

Chemistry ma’am · 2 steps

Hinsberg's reagent needs an N–H to replace, so look for a hydrogen on nitrogen in each structure.

1. What the reagent does. Hinsberg's reagent is benzenesulphonyl chloride, C₆H₅SO₂Cl. The amine nitrogen attacks the sulphur and loses an H from nitrogen along with Cl as HCl, giving a sulphonamide. No H on nitrogen means no reaction.

   R-NH₂ + C₆H₅SO₂Cl → C₆H₅SO₂NHR + HCl

   Compound	Type	H on N	Reacts?
   A: aniline, C₆H₅NH₂	1°	2	yes
   B: N,N-dimethylaniline, C₆H₅N(CH₃)₂	3°	0	no
   C: methylamine, CH₃NH₂	1°	2	yes
   D: trimethylamine, N(CH₃)₃	3°	0	no
   E: diphenylamine, (C₆H₅)₂NH	2°	1	yes

2. So. The primary amines A and C and the secondary amine E react, while the tertiary amines B and D do not. The answer is (a).

The idea to keep. Hinsberg's test sorts amines by the H on nitrogen: 1° and 2° amines react, 3° amines do not. The 1° sulphonamide dissolves in alkali, the 2° one does not.

Answer from the NTA final answer key. Solution by PrepWiser.