Which one of the following statements is correct for electrolysis of brine solutions?

Options

A. `OH^(-)` is formed at cathode
B. `Cl_(2)` is formed at cathode
C. `O_(2)` is formed at cathode
D. `H_(2)` is formed at cathode

Answer

To solve the question regarding the electrolysis of brine solutions, we will analyze the process step by step.

### Step-by-Step Solution:

1. **Understanding Brine Solution**:
- Brine is a concentrated solution of sodium chloride (NaCl) in water. When we perform electrolysis on brine, it dissociates into its constituent ions: Na⁺ (sodium ions) and Cl⁻ (chloride ions).

2. **Identifying the Electrodes**:
- In electrolysis, we have two electrodes: the anode (positive electrode) and the cathode (negative electrode).
- The Na⁺ ions will migrate towards the cathode, while the Cl⁻ ions will migrate towards the anode.

3. **Reactions at the Anode**:
- At the anode, oxidation occurs. The chloride ions (Cl⁻) lose electrons to form chlorine gas (Cl₂).
- The half-reaction at the anode can be written as:
\[ 2 \text{Cl}^- \rightarrow \text{Cl}_2 + 2 \text{e}^- \]

4. **Reactions at the Cathode**:
- At the cathode, reduction occurs. Although Na⁺ ions are present, water (H₂O) has a higher reduction potential than sodium ions. Therefore, water will be reduced instead of sodium ions.
- The half-reaction at the cathode can be written as:
\[ 2 \text{H}_2\text{O} + 2 \text{e}^- \rightarrow \text{H}_2 + 2 \text{OH}^- \]

5. **Summary of Products**:
- From the reactions above, we can summarize that:
- Chlorine gas (Cl₂) is produced at the anode.
- Hydrogen gas (H₂) and hydroxide ions (OH⁻) are produced at the cathode.

6. **Evaluating the Statements**:
- Now, we will evaluate the given statements:
1. OH⁻ is formed at the cathode. (Correct)
2. Cl₂ is formed at the cathode. (Incorrect, it is formed at the anode)
3. O₂ is formed at the cathode. (Incorrect, H₂ is formed)
4. H₂ is formed at the cathode. (Correct)

7. **Conclusion**:
- The correct statements regarding the electrolysis of brine are:
- OH⁻ is formed at the cathode.
- H₂ is formed at the cathode.

### Final Answer:
The correct statements are that OH⁻ is formed at the cathode and H₂ is formed at the cathode.