Which of the following is a disproportionation reaction?

Options

A. `Cl_(2(g))+2OH_((aq))^(-)rarrClO_((aq))^(-)+Cl_((aq))^(-)+H_(2)O_((l))`
B. `Cl_(2(g))+2I_((aq))^(-)rarr 2Cl_((aq))^(-)+I_(2(s))`
C. `2Fe_((s))+3H_(2)O_((l))overset(Delta)rarr Fe_(2)O_(3(s))+3H_(2(g))`
D. `2H_(2)O_((l))+2F_(2(g))rarr 4HF_((aq))+O_(2(g))`

Explanation

To determine which of the given reactions is a disproportionation reaction, we need to understand what a disproportionation reaction is. A disproportionation reaction is a specific type of redox reaction in which a single element undergoes both oxidation and reduction, resulting in two different products with different oxidation states.

### Step-by-Step Solution:

1. **Identify the Reactions**: We need to analyze the given options (A, B, C, D) to see if any of them involve a single element being both oxidized and reduced.

2. **Analyze Option A**:
- The reaction involves Cl2 in a basic medium producing ClO⁻ and Cl⁻.
- **Oxidation States**:
- In Cl2, the oxidation state of Cl is 0.
- In ClO⁻, the oxidation state of Cl can be calculated as follows:
- Let the oxidation state of Cl be X. The oxidation state of O is -2.
- The overall charge of ClO⁻ is -1, so: X + (-2) = -1 → X = +1.
- In Cl⁻, the oxidation state of Cl is -1.
- **Changes**:
- Cl changes from 0 (in Cl2) to +1 (in ClO⁻) → Oxidation (loss of electrons).
- Cl changes from 0 (in Cl2) to -1 (in Cl⁻) → Reduction (gain of electrons).
- Since Cl is both oxidized and reduced, this is a disproportionation reaction.

3. **Analyze Option B**:
- Chlorine is reduced and iodine is oxidized.
- Here, we do not have a single element undergoing both oxidation and reduction, so this is not a disproportionation reaction.

4. **Analyze Option C**:
- Iron (Fe) is oxidized and water is reduced.
- Again, there is no single element undergoing both oxidation and reduction, so this is not a disproportionation reaction.

5. **Analyze Option D**:
- Fluorine is reduced and water is oxidized.
- Similar to the previous options, there is no single element undergoing both oxidation and reduction, so this is not a disproportionation reaction.

6. **Conclusion**: Based on the analysis, only Option A involves a single element (Cl) that is both oxidized and reduced. Therefore, the answer is:

**Answer: A (Cl2 in basic medium producing ClO⁻ and Cl⁻)**