According to the adsorption theory of catalysis, the speed of a reaction increases because adsorption of reactant molecules onto the surface of the catalyst lowers the activation energy barrier for the reaction. This makes it easier for reactant molecules to undergo the reaction and increase the reaction rate.
So, the correct option is (D): Adsorption lowers the activation energy of the reaction.
All reactants need to overcome certain energy, better known as activation energy in order to form products. This activation energy is the difference between the energy of the transition state and the reactant species.
Catalysis of chemical reactions is generally divided into two categories: