If the half of a reactant is independent of its initial concentration, then the order of the reaction is:

Question

Question

This question was previously asked in

DSSSB PGT Chemistry (Female) Official Paper (Held On: 06 Jul, 2018 Shift 1)

Answer 1

CONCEPT:

Half-Life (t_1/2) and Reaction Order

The half-life of a reaction is the time required for half of the reactant to be consumed.
The relationship between half-life and the order of a reaction depends on the rate law:
- For a zero-order reaction, t_1/2 is directly proportional to the initial concentration of the reactant ([A]₀).
- For a first-order reaction, t_1/2 is independent of the initial concentration of the reactant ([A]₀).
- For a second-order reaction, t_1/2 is inversely proportional to the initial concentration of the reactant ([A]₀).

qImage685bf10f2b393fcce17d2500

EXPLANATION:

The problem states that the half-life of the reactant is independent of its initial concentration.
This behavior is characteristic of a first-order reaction.
For a first-order reaction, the half-life is calculated using the formula:
t_1/2 = 0.693 / k
Since t_1/2 depends only on the rate constant (k) and not on the initial concentration ([A]₀), the reaction is first-order.

Therefore, the correct answer is The order of the reaction is 1.