(a) Solid manganese(IV) oxide, MnO2, catalyses the decomposition of hydrogen peroxide. 2H2O2(aq) → 2H2O(l) + O2(g) State the type of catalysis for this reaction. Explain your answer. [1] (b) Hydrogen peroxide reacts with iodide ions in acidic conditions as shown. H2O2 + 2I¯ + 2H+ → 2H2O + I2 The initial rate of this reaction is investigated with different concentrations of H2O2, I and H+. The results obtained are shown in Table 3.1. Table 3.1 experiment [H2O2]/mol dm⁻³ [I]/mol dm⁻³ [H+]/moldm⁻³ initial rate/mol dm⁻³ s⁻¹ 1 0.0450 0.0300 0.0125 2.42 x 10⁻³ 2 0.0225 0.0600 0.0125 2.42 x 10⁻³ 3 0.0225 0.120 0.0125 4.84 x 10⁻³ 4 0.0450 0.120 0.0500 9.68 x 10⁻³ (i) Use the information in Table 3.1 to deduce the rate equation for this reaction. Explain your reasoning. [4] (ii) Use your rate equation from (b)(i) and the data from Experiment 1 to calculate the rate constant, k, for this reaction. Include the units of k. k = units [2] (c) The rate of the thermal decomposition of azomethane, CH3N=NCH3, is investigated. CH3N=NCH3 → N2 + C2H6 Fig. 3.1 shows the results obtained. The reaction is first order with respect to CH3N=NCH3. [Figure 3.1] (i) Use Fig. 3.1 to calculate two half-lives, t₁/₂, to show that the reaction is first order. [2] (ii) Use your answer to (c)(i) to calculate the rate constant, k, for the decomposition of azomethane. k = s⁻¹ [1] (d) Describe the effect of increasing temperature on the rate constant and on the rate of a reaction. [1]