Question

When initial concentration of the reactant is doubled , the half-life period of a zero order reaction

• A. remains unchanged
• B. is halved
• C. is tripled
• D. is doubled

Answer 1

The Correct Option is D

To solve this question, we need to understand the concept of the half-life of a zero-order reaction.

The half-life (t_{1/2}) of a zero-order reaction is given by the formula:

t_{1/2} = \frac{[A]_0}{2k}

where [A]_0 is the initial concentration of the reactant and k is the rate constant.

Let's analyze what happens when we double the initial concentration of the reactant:

1. Initially, consider the initial concentration as [A]_0. The half-life will be t_{1/2} = \frac{[A]_0}{2k}.
2. If the initial concentration is doubled, it becomes 2[A]_0.
3. Plugging this new concentration into the formula, the new half-life is:

t'_{1/2} = \frac{2[A]_0}{2k} = \frac{[A]_0}{k}

Comparing the new half-life to the original:

t'_{1/2} = 2 \times \frac{[A]_0}{2k} = 2 \times t_{1/2}

This indicates that the half-life is doubled when the initial concentration is doubled.

Therefore, the correct answer is: is doubled.