It takes 40 min for the completion of 50% of the reaction: A -> Products. For the completion of next — Chemical Kinetics Chemistry Question

💡 Solution & Explanation

Starting with initial concentration C_0, the first half-life t_1/2(1) = 40 min. The next 50% completion represents the reaction from 0.5 C_0 to 0.25 C_0, which takes t_1/2(2) = 80 min. Thus, halving the concentration doubles the half-life: t_1/2 ∝ 1/C_0. Since t_1/2 ∝ C_0^(1-n) => 1-n = -1 => n = 2. Therefore, the reaction is of second-order.