Azo dye test is given by

Options

A. All amines
B. Only secondary amin e
C. Only primary aliphatic amine
D. `Only primary aromatic amine

Answer

### Step-by-Step Solution:

1. **Understanding the Azo Dye Test**: The Azo dye test is a chemical test used to identify the presence of primary aromatic amines. It is specifically designed to distinguish between primary aromatic amines and other types of amines, such as aliphatic primary amines.

2. **Identifying the Reactants**: In the Azo dye test, the primary aromatic amine (for example, aniline, which has the structure C6H5NH2) reacts with nitrous acid (HONO) in the presence of hydrochloric acid (HCl) to form a diazonium salt.

3. **Formation of Diazonium Chloride**: The reaction can be summarized as follows:
- Aniline (C6H5NH2) + Nitrous acid (HONO) + HCl → Benzene diazonium chloride (C6H5N2Cl) + Water (H2O)
- The diazonium chloride is characterized by the presence of the -N2+ group.

4. **Reaction with Naphthol**: The benzene diazonium chloride then reacts with 2-naphthol (C10H7OH) in a basic medium (dilute NaOH, pH 9-10) to produce an azo dye.
- The reaction can be summarized as:
- Benzene diazonium chloride + 2-naphthol → Azo dye (orange or red colored compound) + HCl

5. **Observation of Color Change**: The formation of an orange or red dye indicates a positive result for the presence of primary aromatic amines. This color change is a visual confirmation of the reaction.

6. **Conclusion**: The Azo dye test is specifically indicative of primary aromatic amines, and therefore, the answer to the question "Azo dye test is given by" is that it is given by primary aromatic amines.

### Final Answer:
The Azo dye test is given by primary aromatic amines.

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