The purpose of addition of KF to HF in the preparation of Fluorine by electrolysis is

Options

A. to increase the conductance of HF
B. to decrease the oxidation potential of HF
C. to lower the solubility of HF
D. to increase the melting point of HF

Answer

To answer the question regarding the purpose of adding KF to HF in the preparation of fluorine by electrolysis, we can break down the solution into clear steps:

### Step-by-Step Solution:

1. **Understanding the Electrolysis of HF**:
- The electrolysis of hydrofluoric acid (HF) can produce fluorine gas (F2) at the anode. However, HF is a weak acid and does not dissociate completely in water, which can limit the efficiency of the electrolysis process.

2. **Role of KF**:
- Potassium fluoride (KF) is added to HF to enhance the electrolysis process. KF is a strong electrolyte and dissociates completely in solution, providing additional fluoride ions (F⁻) that can participate in the electrolysis.

3. **Increasing Conductivity**:
- The addition of KF increases the overall ionic strength and conductivity of the solution. This is important because higher conductivity allows for a more efficient flow of electric current during electrolysis, facilitating the production of fluorine gas.

4. **Decreasing Oxidation Potential**:
- The presence of KF lowers the oxidation potential of HF. This means that it becomes easier for the fluoride ions to be oxidized to form fluorine gas (F2) at the anode. A lower oxidation potential means that less energy is required for the reaction to occur.

5. **Conclusion**:
- Therefore, the main purpose of adding KF to HF in the preparation of fluorine by electrolysis is to **decrease the oxidation potential of HF**, thereby enhancing the efficiency of the electrolysis process and facilitating the generation of fluorine gas.

### Final Answer:
The purpose of addition of KF to HF in the preparation of fluorine by electrolysis is to decrease the oxidation potential of HF, which enhances the efficiency of the electrolysis process.

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