Changing the reactant concentration can significantly affect the efficiency of a chemical reaction, including the decomposition of hydrogen peroxide H2O2 catalyzed by manganese dioxide MnO2 . The efficiency of a reaction can be measured by the reaction rate, which is the speed at which the reactants are converted into products.In the case of hydrogen peroxide decomposition catalyzed by manganese dioxide, the reaction can be represented by the following equation:2 H2O2 aq 2 H2O l + O2 g Manganese dioxide acts as a catalyst, which means it speeds up the reaction without being consumed in the process. The efficiency of this reaction depends on the concentration of hydrogen peroxide, as well as other factors such as temperature, pressure, and the presence of other substances.According to the collision theory, the reaction rate depends on the frequency of effective collisions between the reacting particles. When the concentration of hydrogen peroxide is increased, there are more H2O2 molecules present in the solution, which increases the probability of effective collisions between the reactant molecules and the catalyst surface.As a result, the reaction rate will generally increase as the concentration of hydrogen peroxide is increased. However, this relationship is not always linear, and the reaction rate may not continue to increase indefinitely as the concentration increases. At very high concentrations, the reaction rate may become limited by other factors, such as the availability of active sites on the catalyst surface or the rate at which the products can be removed from the reaction mixture.In summary, increasing the reactant concentration in this case, hydrogen peroxide generally increases the efficiency of the reaction the reaction rate up to a certain point. Beyond that point, other factors may limit the reaction rate, and further increases in concentration may not lead to significant improvements in efficiency.