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

💡 Solution & Explanation

Setting E_A = 0: E_D = -42.8, E_C = 20.8, E_B = 20.8 - 13.2 = 7.6. For transition states: E_TS3 = E_C + 4.3 = 25.1. E_TS1 = E_TS3 + 2.4 = 27.5. E_TS2 = E_TS1 + 10.2 = 37.7. Forward activation energies: Ea(A→B) = 27.5, Ea(B→C) = 30.1, Ea(C→D) = 4.3. The lowest Ea gives the fastest step, which is C → D. Therefore, correct answer is C.