Which of the following compounds gives azo dye test ?

Options

A.
B.
C.
D.

Answer

To determine which of the given compounds gives a positive azo dye test, we need to understand the nature of the compounds involved and the azo dye test itself.

### Step-by-Step Solution:

1. **Understand the Azo Dye Test**:
The azo dye test is used to identify the presence of aromatic amines. When an aromatic amine reacts with nitrous acid (HNO2), it forms a diazonium salt. This diazonium salt can then react with phenolic compounds to form azo dyes, which are typically orange in color.

2. **Identify Aromatic Amines**:
An aromatic amine is characterized by having an amino group (-NH2) directly attached to an aromatic ring (like benzene).

3. **Evaluate the Options**:
- **Option 1**: Cyclohexylamine (not aromatic, as it does not have a benzene ring).
- **Option 2**: Aniline (C6H5NH2), which is an aromatic amine because the amino group is directly attached to the benzene ring.
- **Option 3**: Benzylamine (C6H5CH2NH2), which is not an aromatic amine because the amino group is attached to a carbon that is not part of the aromatic ring.
- **Option 4**: Ethylamine (not aromatic, as it does not have a benzene ring).

4. **Conclusion**:
From the evaluation, only **Option 2: Aniline** is an aromatic amine and will give a positive azo dye test when reacted with nitrous acid and subsequently with a phenolic compound.

### Final Answer:
The compound that gives a positive azo dye test is **Option 2: Aniline**.