On doubling the initial concentration, the half life of a reaction becomes half. The order of the reaction is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 2
For a reaction, if initial concentration is doubled and the half-life becomes half, this matches the behavior of a second-order reaction.
For a second-order reaction:
$t_{1/2} = \frac{1}{k[A]_0}$
So, if $[A]_0$ is doubled, $t_{1/2}$ becomes half.