Which test among the following is not used for the distinction among `1^(@), 2^(@) and 3^(@)` aliphatic amine.

Options

A. Hinsberg's reaget test
B. Carbylamine reaction
C. Azo dye test
D. Action with nitrous acid

Explanation

To determine which test is not used for distinguishing between 1° (primary), 2° (secondary), and 3° (tertiary) aliphatic amines, we can analyze the common tests used for this purpose.

### Step-by-Step Solution:

1. **Identify the Tests Used for Distinction:**
- **Hinsberg Reagent Test:** This test is used to differentiate between primary, secondary, and tertiary amines. Primary amines react to form soluble sulfonamides, secondary amines form insoluble sulfonamides, and tertiary amines do not react.
- **Carbylamine Reaction:** This reaction is specific to primary amines. It does not occur with secondary or tertiary amines.
- **Reaction with Nitrous Acid (HNO2):** Primary amines react with nitrous acid to form nitrogen gas (effervescence), secondary amines form nitrosamines, and tertiary amines form nitrite salts.

2. **Analyze Each Test:**
- **Hinsberg Reagent Test:** Used for all three types of amines.
- **Carbylamine Reaction:** Only applicable for primary amines.
- **Nitrous Acid Reaction:** Used for all three types of amines.

3. **Identify the Test Not Used for Distinction:**
- The **Carbylamine Reaction** is the only test that is not used to distinguish between all three types of amines since it only applies to primary amines.

### Conclusion:
The test that is not used for the distinction among 1°, 2°, and 3° aliphatic amines is the **Carbylamine Reaction**.

---