Which of the following statement is incorrect?

Options

A. benzenediazonium chloride is a colourless crystalline solid
B. benzenediazonium chloride is readily soluble in water
C. benzenediazonium fluoroborate is soluble in water
D. benzene diazonium fluoroborate is stable at room temperature

Answer

To determine which statement is incorrect regarding benzene diazonium compounds, we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Benzene Diazonium Compounds**:
- Benzene diazonium chloride (C6H5N2Cl) and benzene diazonium fluoroborate (C6H5N2BF4) are both arene diazonium salts. They contain a diazo group (N≡N⁺) attached to a benzene ring.

2. **Analyzing Each Statement**:
- **Statement 1**: "Benzene diazonium chloride is a colorless crystalline solid."
- **Analysis**: This statement is **correct**. Benzene diazonium chloride is indeed a colorless crystalline solid.

- **Statement 2**: "Benzene diazonium chloride is readily soluble in water."
- **Analysis**: This statement is also **correct**. Benzene diazonium chloride is known to be soluble in water due to its ionic nature.

- **Statement 3**: "Benzene diazonium fluoroborate is soluble in water."
- **Analysis**: This statement is **incorrect**. Benzene diazonium fluoroborate contains the BF4⁻ ion, which is non-polar, making the compound insoluble in polar solvents like water.

- **Statement 4**: "Benzene diazonium fluoroborate is stable at room temperature."
- **Analysis**: This statement is **correct**. While diazonium salts are generally unstable, benzene diazonium fluoroborate can be stable under certain conditions, but it is not stable at room temperature for extended periods.

3. **Conclusion**:
- The incorrect statement among the options is **Statement 3**: "Benzene diazonium fluoroborate is soluble in water."

### Final Answer:
The incorrect statement is **Statement 3**.

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