Which of the following reagents can be used to distinguish primary amines from other compounds?

Options

A. Carbylamine reaction
B. Hinsberg reaction
C. Action of nitrous acid
D. Libermann's nitroso reaction

Answer

To distinguish primary amines from other compounds, we can use several reagents. Here’s a step-by-step solution to identify the appropriate reagents:

### Step 1: Understand the Types of Amines
Amines can be classified into three categories:
- Primary amines (RNH2)
- Secondary amines (R2NH)
- Tertiary amines (R3N)

### Step 2: Identify the Reagents
The question asks for reagents that can specifically distinguish primary amines from secondary and tertiary amines. The following reagents can be used:
1. **Carbylamine Test**
2. **Hinsberg Test**
3. **Action of Nitrous Acid**

### Step 3: Carbylamine Test
The Carbylamine test is specific for primary amines. When a primary amine reacts with chloroform (CHCl3) in the presence of a base (like KOH), it forms a foul-smelling gas called isocyanide (or carbylamine). Secondary and tertiary amines do not give this test.

### Step 4: Hinsberg Test
The Hinsberg test can distinguish between primary, secondary, and tertiary amines. In this test, the amine is treated with benzenesulfonyl chloride. Primary amines form a soluble sulfonamide, while secondary amines form an insoluble sulfonamide, and tertiary amines do not react. This test can help confirm the presence of primary amines.

### Step 5: Action of Nitrous Acid
The action of nitrous acid (HNO2) can also distinguish primary amines. When a primary amine reacts with nitrous acid, it forms a diazonium salt, which is a characteristic reaction of primary amines. However, this reaction is specific to aliphatic primary amines and does not occur with aromatic amines.

### Step 6: Conclusion
From the above tests, we can conclude that:
- The **Carbylamine test** is specific for primary amines.
- The **Hinsberg test** can distinguish all three types of amines.
- The **Action of nitrous acid** can be used for aliphatic primary amines.

### Final Answer
The reagents that can be used to distinguish primary amines from other compounds include:
1. Carbylamine Test
2. Hinsberg Test
3. Action of Nitrous Acid