Assertion:- If some `PCl_(3)(g)` containing labelled (radio active) phosphoros `P^(3l)` is added to a system with following equilibrium, after sometime the system was found to some radioactive `PCl_(3)`
`PCl_(3)(g)hArrPCl_(3)(g)+Cl_(3)(g)`
Reason:- Chemical equilibrium is static in nature.

Options

A. If both Assertion `&` Reason are True `&` the Reason is a correct explanation of the Assertion.
B. If both Assertion `&` Reason are True but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is False.
D. If both Assertion `&` Reason are False.

Answer

To solve the question, we need to analyze the assertion and the reason provided.

### Step-by-step Solution:

1. **Understanding the Assertion**:
- The assertion states that if some \( PCl_3(g) \) containing labeled (radioactive) phosphorus \( P^{31} \) is added to a system at equilibrium, after some time, the system will contain some radioactive \( PCl_3 \).
- This is true because when \( PCl_3 \) is added to the equilibrium system, the radioactive phosphorus will mix with the existing \( PCl_3 \) in the system. As a result, some of the \( PCl_3 \) in the equilibrium will become radioactive.

2. **Understanding the Reason**:
- The reason states that chemical equilibrium is static in nature.
- This statement is false. Chemical equilibrium is actually dynamic in nature. This means that, at equilibrium, the rate of the forward reaction is equal to the rate of the backward reaction, and both reactions continue to occur, but there is no net change in the concentrations of the reactants and products.

3. **Conclusion**:
- Since the assertion is true and the reason is false, the correct answer is that the assertion is true but the reason is false.

### Final Answer:
- The assertion is true, and the reason is false.