A catalyst provides an alternative pathway for a reaction with an activation energy…
CHEMISTRY · Single correct · A Level · Chemistry · Kinetics · Kinetics
Problem
A catalyst provides an alternative pathway for a reaction with an activation energy of 80kJmol−1 in the uncatalyzed process. The catalyzed pathway has an activation energy of 30kJmol−1. Assuming temperature and all other conditions remain the same, which statement best compares the rates of the catalyzed and uncatalyzed reactions?
(a) Both reactions proceed at the same rate because a catalyst changes only the reaction enthalpy, not the activation energy.
(b) Rates cannot be compared unless the reactant concentrations are known.
(c) The catalyzed reaction is significantly faster because many more collisions surmount the lower activation energy barrier.
(d) The catalyzed pathway could actually be slower because formation of a catalyst–intermediate adds extra mechanistic steps that lengthen the process.