What is the concentration of 'A' when d[A]/dt + d[C]/dt = 0? — Chemical Kinetics Chemistry Question

💡 Solution & Explanation

By mass conservation, A+B+C = constant, so d[A]/dt + d[B]/dt + d[C]/dt = 0. The given condition implies d[B]/dt = 0, which occurs at t_max = 20 min. At t = 20 min, [A] = e^(-0.04 × 20) = e^-0.8. Given e^-0.8 = 0.45, [A] = 0.45 M. Therefore, correct answer is B.