The gases liberated during the electrolysis of aqueous solution of hydrogen fluoride 

Options

A. `H_2 and O_2`
B. `H_2 and F_2`
C. `O_2 and F_2`
D. can not be electrolysed

Answer

To determine the gases liberated during the electrolysis of an aqueous solution of hydrogen fluoride (HF), we can follow these steps:

### Step 1: Understand the Electrolysis Process
Electrolysis involves passing an electric current through an electrolyte to cause a chemical change. In this case, we have an aqueous solution of hydrogen fluoride.

### Step 2: Ionization of Hydrogen Fluoride and Water
When HF is dissolved in water, it ionizes to produce hydrogen ions (H⁺) and fluoride ions (F⁻):
\[ \text{HF} \rightarrow \text{H}^+ + \text{F}^- \]

Additionally, water also ionizes to produce hydrogen ions (H⁺) and hydroxide ions (OH⁻):
\[ \text{H}_2\text{O} \rightarrow \text{H}^+ + \text{OH}^- \]

### Step 3: Identify the Ions Present
From the ionization, we have the following ions in the solution:
- H⁺ (from HF and water)
- F⁻ (from HF)
- OH⁻ (from water)

### Step 4: Determine the Reactions at the Electrodes
- **At the Cathode (Reduction occurs)**: The H⁺ ions will migrate to the cathode, where they will gain electrons and be reduced to form hydrogen gas (H₂):
\[ 2 \text{H}^+ + 2e^- \rightarrow \text{H}_2 \]

- **At the Anode (Oxidation occurs)**: The OH⁻ ions will migrate to the anode, where they will lose electrons and be oxidized. Four OH⁻ ions will combine to form oxygen gas (O₂) and water:
\[ 4 \text{OH}^- \rightarrow \text{O}_2 + 2 \text{H}_2\text{O} + 4e^- \]

### Step 5: Identify the Gases Liberated
From the reactions at the electrodes, we can conclude that:
- Hydrogen gas (H₂) is liberated at the cathode.
- Oxygen gas (O₂) is liberated at the anode.

### Final Answer
The gases liberated during the electrolysis of an aqueous solution of hydrogen fluoride are hydrogen (H₂) and oxygen (O₂).

---