For a reaction, half-life (t_1/2) is observed to be independent of the initial concentration of reactants. What is the order of reaction

First order reaction

The half-life of a reaction is the time in which the concentration of a reactant is reduced to half of its initial concentration. It is represented as t_1/2.

We know that, for a first-order reaction,

k = rate constant of first order reaction

t = time

R’ = initial concentration of reactant

R = concentration of reactant

Now at half life, R = R’/2 ( according to above definition )

(∵ log2 = 0.301)

hence, its independent of concentration.