Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): For a reaction with rate constant k = 2.0 10⁻³ s ⁻¹ , the time required for the concentration of reactant to drop from 0.5 M to 0.125 M is exactly the same as the time required to drop from 0.1 M to 0.025 M . Reason (R): The unit of the rate constant indicates that the reaction is of first order, a

Step-by-step solution

The unit of the rate constant ( k = 2.0 10⁻³ s ⁻¹ ) is s ⁻¹ , which confirms that it is a first-order reaction. For a first-order reaction, the time taken for the concentration to reduce to a specific fraction is independent of the initial concentration. In the first case, the concentration drops from 0.5 M to 0.125 M , which is a reduction to 1 4 th of the initial value (i.e., exactly 2 half-lives). In the second case, the concentration drops from 0.1 M to 0.025 M , which is also a reduction to 1 4 th of the initi