Half-life period of a .......... order reaction is ............ of the concentration of the reactant.

Explanation

### Step-by-Step Solution:

1. **Understanding Half-Life in Chemical Kinetics**:
- The half-life of a reaction is the time required for the concentration of a reactant to decrease to half of its initial value. It varies with the order of the reaction.

2. **Zero-Order Reactions**:
- For zero-order reactions, the half-life (t₁/₂) is given by the formula:
\[
...