The compound which gives an oily nitrosoamine on reaction with nitrous acid at low temperature is

Options

A. `CH_(3)NH_(2)`
B. `(CH_(3))_(2)CHNH_(2)`
C. `CH_(3)-NH-CH_(3)`
D. `(CH_(3))_(3)N`

Explanation

To determine the compound that gives an oily nitrosoamine upon reaction with nitrous acid (HNO2) at low temperature, we need to analyze the behavior of different types of amines when they react with nitrous acid.

### Step-by-Step Solution:

1. **Identify the Types of Amines**:
- Amines can be classified into three categories: primary (1°), secondary (2°), and tertiary (3°) amines.
- Primary amines (RNH2) react with nitrous acid to produce nitrogen gas (N2) and an alcohol.
- Secondary amines (R2NH) react with nitrous acid to form nitrosoamines.
- Tertiary amines (R3N) do not react with nitrous acid.

2. **Focus on Secondary Amines**:
- Since we are looking for a compound that gives an oily nitrosoamine, we should focus on secondary amines.
- Secondary amines react with nitrous acid to yield nitrosoamines, which are typically oily liquids.

3. **Example of a Secondary Amine**:
- Consider dimethylamine (CH3)2NH.
- When dimethylamine reacts with nitrous acid, it forms N-nitroso-N-methylamine, which is a yellow oily liquid.

4. **Reaction Mechanism**:
- The reaction can be summarized as follows:
- (CH3)2NH + HNO2 → N-nitroso-N-methylamine (oily liquid) + by-products.
- The oily nature of the product is characteristic of nitrosoamines derived from secondary amines.

5. **Conclusion**:
- The compound that gives an oily nitrosoamine upon reaction with nitrous acid at low temperature is a secondary amine, such as dimethylamine.

### Final Answer:
The compound which gives an oily nitrosoamine on reaction with nitrous acid at low temperature is dimethylamine (or any other secondary amine).