Which is the faster step in the backward direction? — Chemical Kinetics Chemistry Question

💡 Solution & Explanation

Backward activation energies are calculated from the TS energies minus product energies: Ea(B→A) = 27.5 - 7.6 = 19.9; Ea(C→B) = 37.7 - 20.8 = 16.9; Ea(D→C) = 25.1 - (-42.8) = 67.9. The lowest backward activation energy is 16.9 for C → B, making it the fastest. Therefore, correct answer is B.