In a first-order reaction A→B, if k is rate constant and initial concentration of the reactant A is 0.5 M then the half-life is:

Explanation

To find the half-life of a first-order reaction \( A \rightarrow B \) with an initial concentration of \( A \) equal to 0.5 M, we can use the formula for the half-life of a first-order reaction.

### Step-by-Step Solution:

1. **Understand the Formula for Half-Life**:
The half-life (\( t_{1/2} \)) of a first-order reaction is given by the formula:
\[
t_{1/2} = \frac{0.693}{k}
...