Question

The Half Life period of a reaction becomes hard when initial concentration of reactant is doubled then the order of the reaction is

Answer 1

This reaction must be 2nd order. The half-life expression for a 2nd order reaction is:

​​​​​​A --------->B

t_1/2 = 1 / [A] x k
t_1/2 = 1 / [2A] x k = ​​​​​​​t_1/2 = (1/2) x 1/ [A] x k

Here we see that, if [A] is doubled, the half-life is halved.

The reaction is 2nd order.