Assertion (A): `PbCl_(2)` is more stable than `PbCl_(4)`.
Reason (R ): `PbCl_(4)` is a powerful oxidising agent.

Options

A. If both `(A)` and `(R )` are correct and `(R )` is the correct explanation of `(A)`.
B. If both `(A)` and `(R )` are correct but `(R )` is not the correct explanation of `(A)`.
C. If `(A)` is correct but `(R )` is incorrect.
D. If `(A)` and `(R )` are incorrect.

Explanation

To analyze the assertion and reason provided in the question, we will break down the concepts related to the stability of lead(II) chloride (PbCl₂) and lead(IV) chloride (PbCl₄), as well as the properties of oxidizing agents.

### Step 1: Understanding the Assertion
The assertion states that PbCl₂ is more stable than PbCl₄.

- **Stability of PbCl₂ and PbCl₄**:
- PbCl₂ has lead in the +2 oxidation state, which is generally more stable due to the lower oxidation state of lead compared to the +4 oxidation state in PbCl₄.
- The +4 oxidation state is less stable because it is more prone to reduction, meaning it can easily lose electrons to revert to a more stable state (like PbCl₂).

### Step 2: Understanding the Reason
The reason states that PbCl₄ is a powerful oxidizing agent.

- **Oxidizing Agent**:
- An oxidizing agent is a substance that gains electrons in a chemical reaction and, in doing so, causes another substance to be oxidized (lose electrons).
- PbCl₄, being in the +4 oxidation state, is indeed a powerful oxidizing agent because it can easily accept electrons to reduce itself to PbCl₂ (where lead is in the +2 oxidation state).

### Step 3: Evaluating the Relationship between Assertion and Reason
- Both the assertion (PbCl₂ is more stable than PbCl₄) and the reason (PbCl₄ is a powerful oxidizing agent) are correct statements.
- However, the reason does not directly explain why PbCl₂ is more stable than PbCl₄. The stability of PbCl₂ is due to the lower oxidation state of lead, while the oxidizing nature of PbCl₄ is a separate characteristic.

### Conclusion
Based on the analysis:
- Assertion (A) is true: PbCl₂ is more stable than PbCl₄.
- Reason (R) is true: PbCl₄ is a powerful oxidizing agent.
- However, R does not provide a correct explanation for A.

Thus, the correct option is that both the 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 reason is not the correct explanation for the assertion.**