Three different elementary reactions (A, B, and C) each have a one-step energy profile. Their key energy values are listed below.
Reaction A: Reactants = 25 kJ mol−1, Transition state = 95 kJ mol−1, Products = 10 kJ mol−1
Reaction B: Reactants = 30 kJ mol−1, Transition state = 70 kJ mol−1, Products = 55 kJ mol−1
Reaction C: Reactants = 15 kJ mol−1, Transition state = 110 kJ mol−1, Products = 5 kJ mol−1
Consider the information above and answer the following.
(a) Rank the three reactions in order of increasing activation energy for the forward direction. Clearly indicate any ties.
(b) Rank the three reactions in order of decreasing magnitude of the overall energy change ∣ΔE∣. Clearly indicate any ties.
(c) If all three reactions are carried out at the same temperature in identical conditions, which reaction would you predict to have the fastest forward rate? Justify your answer with reference to the energy profile data.
(d) For the reaction you identified in part (c), calculate the activation energy for the reverse direction and state whether the reverse process is endothermic or exothermic.