For a hypothetical reaction `Ararr B`, the rate constain is `0.25 s^(-1)`. If the concentration of `A` is reduced to half, then the value of rate constant is

Options

A. `0.25 s^(-1)`
B. `0.30 s^(-1)`
C. `0.075 s^(-1)`
D. `2.25 s^(-1)`

Explanation

To solve the problem, we need to understand the relationship between the rate constant and the concentration of reactants in a chemical reaction.

### Step-by-Step Solution:

1. **Identify the Reaction**: We have a hypothetical reaction where A is converted to B, represented as \( A \rightarrow B \).

2. **Given Information**:
- The rate constant \( k \) for the reaction is given as \( 0.25 \, s^{-1} \).
- The concentration of A is reduced to half.

3. **Understanding Rate Constant**:
- The rate constant \( k \) is a proportionality constant that relates the rate of a reaction to the concentration of the reactants.
- Importantly, the rate constant is independent of the concentration of the reactants. It only changes with temperature or the nature of the reaction.

4. **Conclusion**:
- Since the concentration of A is halved, it does not affect the value of the rate constant \( k \).
- Therefore, the value of the rate constant remains \( 0.25 \, s^{-1} \) even after the concentration change.

5. **Final Answer**: The value of the rate constant is \( 0.25 \, s^{-1} \).