Two gas-phase elementary reactions occur separately at 298 K
CHEMISTRY · Single correct · A Level · Chemistry · Kinetics · Kinetics
Problem
Two gas-phase elementary reactions occur separately at 298 K.
I. Cl + CH₃Br → CH₃Cl + Br (Ea = 12 kJ mol⁻¹)
II. NO + O₃ → NO₂ + O₂ (Ea = 95 kJ mol⁻¹)
Assuming comparable collision frequencies and orientations, which statement best compares their instantaneous reaction rates at 298 K?
(a) Reaction II is faster because a higher activation energy leads to more energetic collisions.
(b) Both reactions proceed at nearly the same rate since they are carried out at the same temperature.
(c) Reaction I is faster primarily because a larger fraction of collisions exceed the required energy.
(d) Reaction II is faster because forming stronger bonds in the products releases more energy, accelerating the reaction.