Let's consider the reaction of the decomposition of hydrogen peroxide H2O2 in the presence of a catalyst, manganese dioxide MnO2 , and analyze how the reaction rate varies with changes in pH within the range of 3 to 9.Reaction: 2 H2O2 aq 2 H2O l + O2 g Catalyst: Manganese dioxide MnO2 pH range: 3 to 9In this reaction, manganese dioxide acts as a heterogeneous catalyst, providing a surface for the decomposition of hydrogen peroxide into water and oxygen gas. The reaction rate is influenced by the pH of the solution, as the acidity or alkalinity can affect the stability of the reactants and the catalyst's activity.At lower pH values acidic conditions , the reaction rate tends to be faster. This is because hydrogen peroxide is more stable in acidic conditions, and the presence of H+ ions from the acidic solution can further facilitate the decomposition process. Additionally, the catalyst MnO2 is more active under acidic conditions.As the pH increases towards neutral and then into the alkaline range, the reaction rate generally decreases. This is because hydrogen peroxide becomes less stable in alkaline conditions, and the presence of OH- ions from the alkaline solution can compete with the decomposition process. Moreover, the activity of the MnO2 catalyst decreases in alkaline conditions.In summary, the reaction rate of the decomposition of hydrogen peroxide in the presence of manganese dioxide catalyst varies with changes in pH, being faster under acidic conditions pH 3 and slower under alkaline conditions pH 9 .