Question

Hinsberg’s reagent is

• A. $HCl/ZnCl_2$
• B. $Sn/HCl$
• C. ammoniacal $AgNO_3$
• D. $FeBr_3$
• E. benzenesulphonyl chloride

Hint:

Remember the solubilities for the Hinsberg test: $1^\circ \to$ Soluble in base; $2^\circ \to$ Insoluble in base; $3^\circ \to$ No reaction.

Answer 1

Answer: (E)

Step 1: Understanding the Concept:
Hinsberg's test is used to distinguish between primary, secondary, and tertiary amines.
Step 2: Key Formula or Approach:
Reagent: \( C_6H_5SO_2Cl \) (Benzenesulphonyl chloride).
Step 3: Detailed Explanation:
- Primary amines react to form a sulphonamide that is soluble in alkali.
- Secondary amines react to form a sulphonamide that is insoluble in alkali.
- Tertiary amines do not react at all.
Other options:
A: Lucas reagent.
C: Tollen's reagent.
Step 4: Final Answer:
Hinsberg's reagent is benzenesulphonyl chloride.