Question

A first order reaction has half life period 34.65 seconds .Its rate constant is?​

Answer 1

The half-life of a first-order reaction is a constant that is related to the rate constant for the reaction: t1/2 = 0.693/k. Radioactive decay reactions are first-order reactions. The rate of decay, or activity, of a sample of a radioactive substance is the decrease in the number of radioactive nuclei per unit time.

Answer 2

Given: A first-order reaction has a half-life period of 34.65 seconds.

To find: We have to find the rate constant.

Solution:

For the first-order reaction, the half-life period of the reaction is a ratio of 0.693 to rate constant.

Thus we can write-

$t = \frac{0.633}{k}$

Where t is the half-life period of the reaction which is 34.65 seconds.

The value of k will be-

$k = \frac{0.693}{34.65} \\ k = 0.02$

The rate constant will be $0.02sec^-$.