Assertion: Aquated copper(I) cation undergoes disproportionation as:
`2Cu^(+)(aq) to Cu^(2+)(aq)+Cu`
Reason: Hydration energy of `Cu^(2+)` is higher than that of `Cu^(+)` which compensates second ionisation energy of Cu.

Options

A. If both assertion and reason are true and the reason is the correct explanation of assertion
B. If both assertion and reason are true and the reason is not the correct explanation of assertion
C. If assertion is false but reason is true
D. If assertion is true but the reason is false

Answer

To solve the question, we need to analyze both the assertion and the reason provided regarding the behavior of the aquated copper(I) cation.

### Step-by-Step Solution:

1. **Understanding Disproportionation Reaction**:
- Disproportionation is a type of redox reaction where a single species is both oxidized and reduced. In this case, the assertion states that the aquated copper(I) cation (Cu⁺) undergoes disproportionation:
\[ 2Cu^{+}(aq) \rightarrow Cu^{2+}(aq) + Cu(s) \]
- Here, one Cu⁺ ion is oxidized to Cu²⁺ (losing an electron), while another Cu⁺ ion is reduced to metallic copper (Cu) (gaining an electron).

2. **Analyzing the Reason**:
- The reason states that the hydration energy of Cu²⁺ is higher than that of Cu⁺, which compensates for the second ionization energy of copper.
- Hydration energy refers to the energy released when ions are surrounded by water molecules. Cu²⁺, having a higher charge density due to its +2 charge, interacts more strongly with water molecules compared to Cu⁺, leading to greater hydration energy.

3. **Comparing Ionization Energies**:
- The second ionization energy of copper (removing an electron from Cu⁺ to form Cu²⁺) is significant. However, the high hydration energy of Cu²⁺ can offset this energy requirement.
- When Cu⁺ loses an electron to become Cu²⁺, the energy released from hydration compensates for the energy needed to remove that electron.

4. **Conclusion**:
- Both the assertion and the reason are true. The assertion correctly describes the disproportionation reaction of Cu⁺, and the reason accurately explains why this reaction occurs based on the hydration energies and ionization energies involved.
- Therefore, the correct answer is that both the assertion and reason are true, and the reason correctly explains the assertion.

### Final Answer:
Both the assertion and reason are true, and the reason is the correct explanation of the assertion.