The decomposition reaction on the two surfaces obeys a rate law of the form 3NH₃(g) ⟶ rate = k[3H₂(g)][4H₂(g)]². How can you explain the inverse dependence of the rate on the H₂ concentration?
a) The H₂ concentration acts as a catalyst, increasing the rate of decomposition.
b) The presence of excess H₂ shifts the equilibrium towards the reactant side, slowing down the reaction rate.
c) H₂ molecules collide less frequently with the surfaces, leading to a decrease in the reaction rate.
d) The reaction is first order with respect to H₂, indicating that doubling its concentration halves the rate.