Name the compound which is used to obtain fluorine gas on electrolysis. At which electrode does `F_2` appears?

Answer

To solve the question regarding the compound used to obtain fluorine gas through electrolysis and the electrode at which F₂ appears, we can follow these steps:

### Step 1: Identify the Compound
The compound used to obtain fluorine gas through electrolysis is potassium hydrogen fluoride, which is represented as KHF₂.

### Step 2: Understand the Electrolysis Process
During the electrolysis of KHF₂ in anhydrous hydrogen fluoride (HF), the compound dissociates and allows for the generation of fluorine gas.

### Step 3: Determine the Electrodes
In electrolysis, there are two electrodes: the anode (positive electrode) and the cathode (negative electrode).

### Step 4: Reaction at the Anode
At the anode, the reaction involves the discharge of fluoride ions (F⁻) from KHF₂. The reaction can be represented as:
\[ \text{2HF}_2^- \rightarrow \text{F}_2 + \text{H}^+ + 2e^- \]
This indicates that fluorine gas (F₂) is produced at the anode.

### Step 5: Reaction at the Cathode
At the cathode, the reaction involves the reduction of hydrogen ions (H⁺) to form hydrogen gas (H₂):
\[ \text{2H}^+ + 2e^- \rightarrow \text{H}_2 \]
This indicates that hydrogen gas (H₂) is produced at the cathode.

### Conclusion
Thus, the compound used to obtain fluorine gas on electrolysis is potassium hydrogen fluoride (KHF₂), and fluorine gas (F₂) appears at the anode.

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