A catalyst increases the rate of reaction by:

Decreasing activation energy

The correct answer is option 2. Decreasing activation energy.

A catalyst increases the rate of a chemical reaction by decreasing the activation energy required for the reaction to occur. Activation energy is the minimum amount of energy that reactant molecules must possess in order to undergo chemical transformation and form products.

By providing an alternative reaction pathway with lower activation energy, a catalyst facilitates the breaking and forming of chemical bonds in the reactant molecules. This lower-energy pathway allows a larger fraction of reactant molecules to have sufficient energy to surpass the energy barrier and undergo the reaction.

The catalyst itself does not change the overall energy changes (enthalpy or internal energy) of the reaction. It simply lowers the energy barrier, making it easier for the reactants to convert into products. As a result, more reactant molecules can participate in successful collisions, leading to an increased rate of reaction.

Therefore, the correct answer is (2) Decreasing activation energy.