When Brine solution is subjected to electrolysis the gases liberated at anode and at cathode are

Options

A. `H_2 and Cl_2`
B. `H_2 and O_2`
C. `Cl_2 and O_2`
D. `Cl_2 and H_2`

Answer

To solve the question regarding the gases liberated at the anode and cathode during the electrolysis of brine solution, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Brine Solution**:
- Brine solution is a saturated solution of sodium chloride (NaCl) in water.

2. **Dissociation of NaCl in Water**:
- When NaCl is dissolved in water, it dissociates into sodium ions (Na⁺) and chloride ions (Cl⁻):
\[ \text{NaCl} \rightarrow \text{Na}^+ + \text{Cl}^- \]

3. **Dissociation of Water**:
- Water also dissociates into hydrogen ions (H⁺) and hydroxide ions (OH⁻):
\[ \text{H}_2\text{O} \rightarrow \text{H}^+ + \text{OH}^- \]

4. **Identify Ions Present**:
- In the brine solution, the ions present are Na⁺, Cl⁻, H⁺, and OH⁻.

5. **Electrolysis Process**:
- During electrolysis, cations migrate towards the cathode (negative electrode) and anions migrate towards the anode (positive electrode).

6. **Reactions at the Cathode**:
- At the cathode, the reduction reaction occurs. The cation with a higher discharge potential will be reduced. In this case, H⁺ ions will gain electrons to form hydrogen gas (H₂):
\[ 2\text{H}^+ + 2e^- \rightarrow \text{H}_2 \uparrow \]

7. **Reactions at the Anode**:
- At the anode, the oxidation reaction occurs. The anion with a higher discharge potential will be oxidized. Here, Cl⁻ ions will lose electrons to form chlorine gas (Cl₂):
\[ 2\text{Cl}^- \rightarrow \text{Cl}_2 + 2e^- \]

8. **Conclusion**:
- The gases liberated during the electrolysis of brine solution are:
- At the cathode: Hydrogen gas (H₂)
- At the anode: Chlorine gas (Cl₂)

### Final Answer:
- The gases liberated at the anode and cathode during the electrolysis of brine solution are Cl₂ (chlorine gas) at the anode and H₂ (hydrogen gas) at the cathode.