Which of the following compounds will not undergo azo coupling reaction with benzene diazonium chloride?

Options

A. Aniline
B. Phenol
C. Anisole
D. Nitrobenzene

Explanation

To determine which of the given compounds will not undergo azo coupling reaction with benzene diazonium chloride, we need to analyze each compound's ability to act as a nucleophile. Azo coupling requires the presence of an electron-rich aromatic compound that can react with the weak electrophile, benzene diazonium chloride.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds given are:
- Aniline (C6H5NH2)
- Phenol (C6H5OH)
- Anisole (C6H5OCH3)
- Nitrobenzene (C6H5NO2)

2. **Understand Benzene Diazonium Chloride**: Benzene diazonium chloride (C6H5N2Cl) is a weak electrophile. It can react with nucleophiles, which are electron-rich species.

3. **Analyze Aniline**:
- Aniline has an amino group (-NH2) which is an electron-donating group.
- The presence of the -NH2 group increases the electron density on the benzene ring, making it electron-rich.
- Therefore, aniline can undergo azo coupling with benzene diazonium chloride.

4. **Analyze Phenol**:
- Phenol has a hydroxyl group (-OH) which also acts as an electron-donating group.
- The -OH group increases the electron density on the benzene ring, making it electron-rich.
- Thus, phenol can also undergo azo coupling with benzene diazonium chloride.

5. **Analyze Anisole**:
- Anisole contains a methoxy group (-OCH3) which is another electron-donating group.
- The -OCH3 group increases the electron density on the benzene ring, making it electron-rich.
- Therefore, anisole can undergo azo coupling with benzene diazonium chloride.

6. **Analyze Nitrobenzene**:
- Nitrobenzene contains a nitro group (-NO2) which is an electron-withdrawing group.
- The -NO2 group decreases the electron density on the benzene ring, making it electron-deficient.
- As a result, nitrobenzene cannot undergo azo coupling with benzene diazonium chloride because it does not have sufficient electron density to react with the weak electrophile.

7. **Conclusion**: Among the given compounds, nitrobenzene will not undergo azo coupling reaction with benzene diazonium chloride due to its electron-withdrawing nature.

### Final Answer:
**Nitrobenzene will not undergo azo coupling reaction with benzene diazonium chloride.**

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