Q44 / 150 · MHT CET 2026 (20 April Shift 2) · Chemistry
Identify the reagent used to distinguish primary and secondary amines by Hinsberg test.
- A$\text{NaNO}_2$ and HCl
- B$\text{FeCl}_3$ (alc)
- Correct answerC$\text{C}_6\text{H}_5\text{SO}_2\text{Cl}$
- D$\text{CHCl}_3$ and KOH (alc)
Solution
Hinsberg test is used to distinguish between primary, secondary, and tertiary amines.
The reagent used in this test is benzenesulfonyl chloride, which has the chemical formula $\text{C}_6\text{H}_5\text{SO}_2\text{Cl}$.
Primary amines react with Hinsberg reagent to form an N-alkylbenzenesulfonamide, which is soluble in alkali due to the presence of an acidic hydrogen attached to nitrogen.
Secondary amines react to form an N,N-dialkylbenzenesulfonamide, which is insoluble in alkali as it lacks an acidic hydrogen.
Tertiary amines do not react with Hinsberg reagent.
Answer: $\text{C}_6\text{H}_5\text{SO}_2\text{Cl}$
The reagent used in this test is benzenesulfonyl chloride, which has the chemical formula $\text{C}_6\text{H}_5\text{SO}_2\text{Cl}$.
Primary amines react with Hinsberg reagent to form an N-alkylbenzenesulfonamide, which is soluble in alkali due to the presence of an acidic hydrogen attached to nitrogen.
Secondary amines react to form an N,N-dialkylbenzenesulfonamide, which is insoluble in alkali as it lacks an acidic hydrogen.
Tertiary amines do not react with Hinsberg reagent.
Answer: $\text{C}_6\text{H}_5\text{SO}_2\text{Cl}$
Hence, the correct answer is option: 'C'.