Which of the following change represents a disproportionation reaction (s) :

Options

A. `Cl_(2)+2OH^(-)rarrClO^(-)+Cl^(-)+H_(2)O`
B. `Cu_(2)O+2H^(+)rarrCu+Cu^(2+)+H_(2)O`
C. `2HCuCl_(2)overset("dilution with")underset("Water")rarrCu+Cu^(2+)+4Cl^(-)+2H^(+)`
D. All of the above

Answer

To determine which of the given changes represents a disproportionation reaction, we need to analyze the oxidation states of the elements involved in each reaction. A disproportionation reaction is characterized by a single substance being simultaneously oxidized and reduced, resulting in two different products.

### Step-by-Step Solution:

1. **Identify the Reactions**:
We need to analyze the provided reactions one by one to find out if any of them show a change in oxidation states for the same element.

2. **Analyze the First Reaction**:
- Let's assume the first reaction involves chlorine (Cl).
- In its elemental form, chlorine has an oxidation state of 0.
- If it forms two products, one being Cl⁻ (oxidation state -1) and another being Cl⁺ (oxidation state +1), we see that:
- Cl changes from 0 to -1 (reduction)
- Cl changes from 0 to +1 (oxidation)
- Since the same element (Cl) is undergoing both oxidation and reduction, this reaction is a disproportionation reaction.

3. **Analyze the Second Reaction**:
- Assume the second reaction involves copper (Cu).
- If we start with Cu in the oxidation state of +1 and it forms Cu⁺ (oxidation state +2) and Cu⁰ (oxidation state 0):
- Cu changes from +1 to +2 (oxidation)
- Cu changes from +1 to 0 (reduction)
- Again, the same element (Cu) is undergoing both oxidation and reduction, indicating this is also a disproportionation reaction.

4. **Analyze the Third Reaction**:
- For the third reaction, let's again consider copper.
- If Cu starts at 0 and forms Cu²⁺ (oxidation state +2) and Cu⁺ (oxidation state +1):
- Cu changes from 0 to +2 (oxidation)
- Cu changes from 0 to +1 (reduction)
- The same element (Cu) is undergoing both oxidation and reduction, confirming that this is also a disproportionation reaction.

5. **Conclusion**:
- Since all three reactions involve the same element undergoing both oxidation and reduction, they all represent disproportionation reactions.
- Therefore, the correct answer is **Option D: All of the above**.