2025 O Level Chem P1 Q32 — Catalysts Solution

Answer: B. A catalyst speeds up a reaction by providing an alternative reaction pathway with a lower activation energy. More particles have enough energy to react when the threshold is lower.

A is wrong: a catalyst doesn't give particles more energy — the temperature is unchanged, so the kinetic energy distribution of the particles is unchanged.

C is wrong: the energy of products is unchanged by a catalyst. The catalyst doesn't appear in the net equation and isn't consumed.

D is wrong: the enthalpy change \(\Delta H\) is unchanged by a catalyst. \(\Delta H\) is determined only by the starting and ending states, both of which the catalyst leaves alone.