The effect of concentration on the reaction rate of catalytic hydrogenation of butene can be explained using the collision theory and the rate law. According to the collision theory, the rate of a reaction depends on the frequency of effective collisions between the reacting molecules. In the case of catalytic hydrogenation of butene, the reactants are butene and hydrogen gas, and the catalyst is usually a metal like palladium or platinum.As the concentration of the reactants butene and hydrogen increases, the number of molecules present in the reaction mixture also increases. This leads to a higher frequency of collisions between the reactant molecules, resulting in a higher reaction rate. Therefore, increasing the concentration of butene and hydrogen will increase the reaction rate of the catalytic hydrogenation process.The rate law for this reaction can be written as:Rate = k [Butene]^m [Hydrogen]^nwhere Rate is the reaction rate, k is the rate constant, [Butene] and [Hydrogen] are the concentrations of butene and hydrogen, and m and n are the reaction orders with respect to butene and hydrogen, respectively.The values of m and n depend on the specific reaction mechanism and can be determined experimentally. For many catalytic hydrogenation reactions, the reaction orders are close to 1, indicating a direct proportionality between the concentration of the reactants and the reaction rate.In summary, increasing the concentration of butene and hydrogen in the catalytic hydrogenation reaction will generally lead to an increase in the reaction rate, as it results in a higher frequency of effective collisions between the reactant molecules.