If initial concentration is doubled, the time for half-reaction is also doubled, the order of reaction is

Options

A. zero
B. first
C. second
D. third

Answer

To determine the order of the reaction based on the information provided, we can analyze the relationship between the concentration and the time for half-reaction.

### Step-by-Step Solution:

1. **Understanding Half-Life**: The half-life (t½) of a reaction is the time required for the concentration of a reactant to decrease to half of its initial concentration.

2. **Given Information**:
- When the initial concentration is doubled, the time for half-reaction is also doubled.
- This means if the initial concentration [A] is changed from [A] to 2[A], the half-life changes from t½ to 2t½.

3. **Order of Reaction**:
- For a zero-order reaction, the half-life is independent of the concentration: t½ = [A]₀ / 2k (where k is the rate constant).
- For a first-order reaction, the half-life is constant and does not depend on the concentration: t½ = 0.693 / k.
- For a second-order reaction, the half-life is inversely proportional to the concentration: t½ = 1 / k[A]₀.

4. **Analyzing the Given Data**:
- Since doubling the concentration leads to doubling the half-life, this behavior is characteristic of a second-order reaction. In a second-order reaction, if the concentration is increased, the half-life increases as well.

5. **Conclusion**:
- Therefore, based on the relationship between concentration and half-life, we can conclude that the order of the reaction is **second order**.

### Final Answer:
The order of reaction is **second order**.