Brine is electrolysed by using inert electrodes. The reaction at anode is_______

Options

A. `Cl^(-)(aq) to(1)/(2)Cl_(2)(g)+e^(-)," "E_("Cell")^(ө)=1.36 V`
B. `2H_(2)O(l) to O_(2)(g)+4H^(+)+4e^(-)," "E_("Cell")^(ө)=1.23 V`
C. `Na^(+)(aq)+e^(-)to Na(s)," "E_("Cell")^(ө)=2.71 V`
D. `H^(+)(aq)+e^(-) to (1)/(2)H_(2)(g)," "E_("Cell")^(ө)=0.00 V`

Explanation

To determine the reaction at the anode during the electrolysis of brine using inert electrodes, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Composition of Brine**:
- Brine is a concentrated solution of sodium chloride (NaCl) in water (H2O).

2. **Identify the Electrolysis Process**:
- During electrolysis, brine will dissociate into its ions: Na⁺ and Cl⁻ from NaCl, and H₂O will also dissociate into H⁺ and OH⁻ ions.

3. **Determine the Reactions at the Electrodes**:
- At the anode (positive electrode), oxidation occurs. We need to identify which species can be oxidized:
- Chloride ion (Cl⁻) can be oxidized to chlorine gas (Cl₂).
- Water (H₂O) can be oxidized to oxygen gas (O₂).

4. **Write the Possible Reactions**:
- The possible reactions at the anode are:
- **Oxidation of Chloride**:
\[ 2 \text{Cl}^- (aq) \rightarrow \text{Cl}_2 (g) + 2 \text{e}^- \]
- **Oxidation of Water**:
\[ 2 \text{H}_2\text{O} (l) \rightarrow \text{O}_2 (g) + 4 \text{H}^+ (aq) + 4 \text{e}^- \]

5. **Compare Standard Electrode Potentials**:
- The standard electrode potentials for these reactions are:
- For Cl⁻ to Cl₂: \( E^\circ = +1.36 \, \text{V} \)
- For H₂O to O₂: \( E^\circ = +1.23 \, \text{V} \)

6. **Determine Which Reaction is Preferred**:
- Generally, the reaction with the lower standard electrode potential is preferred for oxidation at the anode. However, due to kinetic factors (overpotential), the reaction with the higher potential (Cl⁻ to Cl₂) occurs more readily in this case.

7. **Conclusion**:
- Therefore, the reaction at the anode during the electrolysis of brine is:
\[ 2 \text{Cl}^- (aq) \rightarrow \text{Cl}_2 (g) + 2 \text{e}^- \]

### Final Answer:
The reaction at the anode is:
\[ 2 \text{Cl}^- (aq) \rightarrow \text{Cl}_2 (g) + 2 \text{e}^- \]