In the extraction of chlorine by electrolysis of brine

Options

A. oxidation of `Cl^(-)`ion to chlorine gas occurs.
B. reduction of `Cl^(-)` ion to chlorine gas occurs.
C. for overall reaction `DeltaG` has negative value.
D. a displacement reaction takes place.

Explanation

### Step-by-Step Solution for the Extraction of Chlorine by Electrolysis of Brine

1. **Understanding Brine**:
- Brine is a concentrated solution of sodium chloride (NaCl) in water. In the context of electrolysis, we often refer to the brine solution rather than molten NaCl.

2. **Electrolysis Setup**:
- In the electrolysis of brine, an electrochemical cell is set up with two electrodes: an anode (positive electrode) and a cathode (negative electrode).

3. **Dissociation of NaCl**:
- When brine (NaCl solution) is subjected to electrolysis, it dissociates into its ions: sodium ions (Na⁺) and chloride ions (Cl⁻).

4. **Oxidation at the Anode**:
- At the anode, oxidation occurs. The chloride ions (Cl⁻) migrate towards the anode where they lose electrons (are oxidized) to form chlorine gas (Cl₂).
- The half-reaction at the anode can be represented as:
\[ 2Cl⁻ \rightarrow Cl₂(g) + 2e⁻ \]

5. **Reduction at the Cathode**:
- At the cathode, reduction occurs. The sodium ions (Na⁺) migrate towards the cathode where they gain electrons (are reduced) to form sodium metal (Na).
- The half-reaction at the cathode can be represented as:
\[ Na⁺ + e⁻ \rightarrow Na(s) \]

6. **Overall Reaction**:
- The overall reaction for the electrolysis of brine can be summarized as:
\[ 2NaCl(aq) + 2H₂O(l) \rightarrow Cl₂(g) + H₂(g) + 2NaOH(aq) \]
- This shows that chlorine gas is produced at the anode, hydrogen gas at the cathode, and sodium hydroxide remains in the solution.

7. **Conclusion**:
- Therefore, the extraction of chlorine gas occurs through the oxidation of chloride ions at the anode during the electrolysis of brine.