Which of the following elements is extracted commercially by the electrolysis of an aqueous solution of its compound ?

Options

A. Cl
B. Br
C. Al
D. Na

Explanation

To determine which element is extracted commercially by the electrolysis of an aqueous solution of its compound, we can analyze the options provided.

### Step-by-Step Solution:

1. **Understanding Electrolysis**: Electrolysis is a chemical process that uses electrical energy to drive a non-spontaneous reaction. In the context of extracting elements, it often involves breaking down compounds into their constituent elements.

2. **Identifying the Options**: We need to consider the elements that can be extracted from their compounds through electrolysis. Common elements extracted via electrolysis include sodium, potassium, magnesium, and chlorine.

3. **Analyzing Chlorine**: Chlorine is typically extracted from an aqueous solution of sodium chloride (NaCl). When an electric current is passed through this solution, chlorine gas is produced at the anode, while hydrogen gas is produced at the cathode. The reaction can be summarized as:
- At the anode: 2Cl⁻ → Cl₂(g) + 2e⁻
- At the cathode: 2H₂O + 2e⁻ → H₂(g) + 2OH⁻

4. **Comparing with Other Elements**:
- **Alkali Metals (e.g., Sodium, Potassium)**: These metals are typically extracted through the electrolysis of their molten salts (fused electrolysis), not from aqueous solutions.
- **Alkaline Earth Metals (e.g., Magnesium)**: Similar to alkali metals, they are also extracted via fused electrolysis.

5. **Conclusion**: Based on the analysis, chlorine is the only element among the options that is extracted commercially by the electrolysis of an aqueous solution of its compound (specifically, NaCl).

### Final Answer:
Chlorine is extracted commercially by the electrolysis of an aqueous solution of its compound (NaCl).

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