What are the limitations of Hinsberg reagent?

Explanation

### Step-by-Step Solution:

1. **Introduction to Hinsberg Reagent**:
- The Hinsberg reagent is benzene sulfonyl chloride, which is used to differentiate between primary, secondary, and tertiary amines based on their solubility and reactivity.

2. **Reactivity of Amines with Hinsberg Reagent**:
- Primary amines (e.g., methyl amine) react with the Hinsberg reagent to form soluble sulfonamides, which can dissolve in alkali solutions.
- Secondary amines do not form soluble sulfonamides and remain insoluble in the reaction mixture.
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