Aryl fluoride may be prepared from arene diazonium chloride using

Options

A. `CuF//HF`
B. `Cu//HF`
C. `HBF_(4)//Delta`
D. `HBF_(4)//NaNO_(2),Cu`

Answer

To prepare aryl fluoride from arene diazonium chloride, follow these steps:

### Step 1: Formation of Arene Diazotization
1. Start with an aniline compound (aromatic amine).
2. Treat the aniline with nitrous acid (HNO2) at a temperature of 273-278 K to form arene diazonium chloride.
- **Chemical Reaction**:
\[ \text{C}_6\text{H}_5\text{NH}_2 + \text{HNO}_2 \rightarrow \text{C}_6\text{H}_5\text{N}_2^+\text{Cl}^- \]

### Step 2: Reaction with Fluoroboric Acid
3. React the arene diazonium chloride with fluoroboric acid (HBF4).
- **Chemical Reaction**:
\[ \text{C}_6\text{H}_5\text{N}_2^+\text{Cl}^- + \text{HBF}_4 \rightarrow \text{C}_6\text{H}_5\text{N}_2^+\text{BF}_4^- + \text{HCl} \]
- This results in the formation of benzene diazonium fluoroborate.

### Step 3: Heating the Diazotization Product
4. Heat the benzene diazonium fluoroborate to induce the elimination of nitrogen gas (N2).
- **Chemical Reaction**:
\[ \text{C}_6\text{H}_5\text{N}_2^+\text{BF}_4^- \xrightarrow{\text{heat}} \text{C}_6\text{H}_5\text{F} + \text{BF}_3 + \text{N}_2 \]
- This step produces aryl fluoride.

### Final Product
5. The final product of this reaction is aryl fluoride (C6H5F).

### Conclusion
The aryl fluoride is prepared from arene diazonium chloride using fluoroboric acid (HBF4) followed by heating.

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