Practice question · Multiple choice
A catalyst can speed a reaction a million-fold and is recovered unchanged at the end. Why does that not violate anything?
Hints
- Sketch the energy profile with and without the catalyst. Which parts of the curve are allowed to move?
- If the catalyst changed the reactant or product energies, what would happen to the equilibrium constant?
Show the answer
B. It lowers the activation barrier by offering another route
Why
Only the barrier moves; the endpoints do not. That is exactly why a catalyst cannot shift an equilibrium, it speeds the forward and reverse directions by the same factor and changes when equilibrium is reached, never where. Supplying or absorbing energy would make it a reactant, and it would not be recovered.
Practise Reaction rates and collision reasoning
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