Q58 / 180 · COMEDK 2026 (9 May Shift 1) · Chemistry
When the initial concentration of a zero order reaction is doubled, the half-life of the reaction is:
- Correct answerAdoubled
- Btripled
- Chalved
- Dnot changed
Solution
For a zero order reaction, the half-life is given by the expression:
$t_{1/2} = \dfrac{[A]_0}{2k}$
where $[A]_0$ is the initial concentration and $k$ is the rate constant.
This shows that the half-life is directly proportional to the initial concentration ($t_{1/2} \propto [A]_0$).
Therefore, when the initial concentration is doubled, the half-life of the reaction is also doubled.
Answer: doubled
$t_{1/2} = \dfrac{[A]_0}{2k}$
where $[A]_0$ is the initial concentration and $k$ is the rate constant.
This shows that the half-life is directly proportional to the initial concentration ($t_{1/2} \propto [A]_0$).
Therefore, when the initial concentration is doubled, the half-life of the reaction is also doubled.
Answer: doubled
Hence, the correct answer is option: 'A'.