Assertion (A): In a first-order reaction, the time required to reduce the reactant concentration from 0.8 M to 0.4 M is exactly the same as the time required to reduce it from 0.4 M to 0.2 M . Reason (R): The half-life of a first-order reaction is given by t_ 1/2 = 0.693 k , which is independent of the initial concentration.

Step-by-step solution

For a first-order reaction, the time required to reduce the concentration of the reactant to half of its initial value is called the half-life, denoted by t_ 1/2 . The reduction from 0.8 M to 0.4 M represents one half-life. Similarly, the reduction from 0.4 M to 0.2 M also represents one half-life. The half-life of a first-order reaction is given by the expression t_ 1/2 = 0.693 k . This expression shows that the half-life is independent of the initial concentration of the reactant. Therefore, the time taken for bo