Concept: A catalyst speeds up a reaction by lowering the activation energy, so less heat is required.
Explanation:When
KClO3 is heated, it decomposes to release oxygen gas.
MnO2 acts as a catalyst in this reaction.
A catalyst provides an alternative reaction pathway with a lower activation energy,
Ea.
This lowers the energy barrier that the reactant particles must overcome for the reaction to occur.
Therefore, only moderate heat is needed because the reaction can proceed at a lower temperature.
Answer: D. lowering the energy barrier of the reaction.