Concept:A catalyst provides an alternative reaction pathway with lower activation energy, without being consumed.
Explanation:The activation energy is the minimum energy needed by reactant particles to form products.
A catalyst increases the reaction rate by lowering this activation energy.
It does not supply energy to the reactants in the process.
It also does not change the equilibrium constant of the reaction, because it affects both forward and backward reactions equally.
With a reduced activation energy, more reactant particles possess the required energy, so the reaction proceeds faster.
Therefore, the correct role of a catalyst is to decrease the activation energy of the reaction.
This makes Option D the correct choice.
Answer:Option D: To decrease activation energy of a reaction