Nitrosoamines `(R_2 N-N=O) `are insoluble in water. On heating them with conc. `H_2 SO_4`, they give sec. amines. The reaction is called

Options

A. Liberman's nitroso reaction
B. Etard's reaction
C. Fries reaction
D. Perkin's reaction.

Explanation

### Step-by-Step Solution

1. **Understanding Nitrosoamines**:
- Nitrosoamines have the general structure \( R_2N-N=O \). They are known to be insoluble in water.

2. **Reaction with Concentrated Sulfuric Acid**:
- When nitrosoamines are heated with concentrated sulfuric acid (\( H_2SO_4 \)), they undergo a reaction that produces secondary amines.

3. **Identifying the Reaction**:
- The reaction that occurs when nitrosoamines are treated with concentrated sulfuric acid is known as the **Lieberman Nitroso Reaction**.

4. **Mechanism of the Reaction**:
- In the Lieberman Nitroso Reaction, the nitrosoamine reacts with sulfuric acid, leading to the formation of secondary amines. This is a characteristic reaction that confirms the presence of secondary amines.

5. **Conclusion**:
- Therefore, the reaction of nitrosoamines with concentrated sulfuric acid to yield secondary amines is called the **Lieberman Nitroso Reaction**.