Assertion : `Cu^+` ion is not stable in aqueous solution.
Reason :` Cu^+` contains 3d-filled subshell.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement

Answer

To solve the assertion and reason question regarding the stability of the `Cu^+` ion in aqueous solution, we will break down the information step by step.

### Step 1: Understand the Assertion
The assertion states that the `Cu^+` ion is not stable in aqueous solution. We need to evaluate whether this statement is true or false.

### Step 2: Analyze the Electronic Configuration of Copper
Copper (Cu) has an atomic number of 29. Its electronic configuration is:
- **Cu:** [Ar] 3d¹⁰ 4s¹

When copper loses one electron to form `Cu^+`, the electronic configuration becomes:
- **Cu⁺:** [Ar] 3d¹⁰ 4s⁰

### Step 3: Stability of `Cu^+` in Aqueous Solution
The `Cu^+` ion is known to be unstable in aqueous solutions. This instability arises because `Cu^+` can easily disproportionate into `Cu` and `Cu^2+`. In aqueous solutions, the `Cu^2+` ion is more stable due to its favorable hydration energy.

### Step 4: Analyze the Reason
The reason provided states that `Cu^+` contains a 3d-filled subshell. While it is true that `Cu^+` has a filled 3d subshell (3d¹⁰), this does not directly explain why `Cu^+` is unstable in aqueous solution.

### Step 5: Conclusion
Both the assertion and the reason are correct statements:
- The assertion that `Cu^+` is not stable in aqueous solution is true.
- The reason that `Cu^+` contains a 3d-filled subshell is also true, but it does not correctly explain the assertion.

Thus, the final conclusion is:
- **Both assertion and reason are correct, but the reason is not the correct explanation for the assertion.**

### Final Answer
Both assertion and reason are correct, but the reason is not the correct explanation for the assertion.

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