Kinetic Treatment of Catalytic Homogeneous Reactions
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Questions and Answers

What is the rate of reaction proportional to in the oxidation of thiosulphate by H2O2 in presence of iodide ions as catalyst?

  • Concentrations of Peroxide and iodide only (correct)
  • Concentrations of Peroxide, thiosulphate, and molbedenic
  • Concentrations of thiosulphate and molbedenic only
  • Concentrations of Peroxide, thiosulphate, and iodide

    • What is the main difference between heterogeneous catalysis and other types of catalysis?

  • The catalyst is in a gaseous phase
  • The catalyst and the reaction mixture are in different phases (correct)
  • The catalyst is homogeneous in nature
  • The catalyst is in a liquid phase

    • What is the product of the hydrogenation of carbon-carbon double bond reaction?

  • CH2CH3
  • CH2=CH2
  • CH3CH2
  • CH3CH3 (correct)

    • What is synthesized by contacting carbon monoxide, carbon dioxide, and hydrogen with copper/zinc oxide catalyst?

    <p>Methanol</p> Signup and view all the answers

    What is the primary function of catalytic converters?

    <p>To reduce the emissions of pollutants</p> Signup and view all the answers

    What type of catalysts are used in catalytic converters?

    <p>Expensive metals like platinum, palladium, and rhodium</p> Signup and view all the answers

    What is the primary mechanism of heterogeneous catalysis?

    <p>All of the above</p> Signup and view all the answers

    What is the result of the reaction between ethene and hydrogen in presence of nickel as a catalyst?

    <p>CH3CH3</p> Signup and view all the answers

    What is the activation energy for the uncatalysed decomposition of hydrogen peroxide?

    <p>75 kJmol-1</p> Signup and view all the answers

    Which catalyst is used in the Haber’s process for the synthesis of ammonia?

    <p>Tungsten</p> Signup and view all the answers

    What is the product of the decomposition of hydrogen iodide?

    <p>H2(g) + I2(g)</p> Signup and view all the answers

    What is the activation energy for the catalysed decomposition of hydrogen peroxide using the enzyme?

    <p>23 kJmol-1</p> Signup and view all the answers

    What is the equation for the decomposition of hydrogen peroxide?

    <p>2 H2O2(aq) ===&gt; 2 H2O(l) + O2(g)</p> Signup and view all the answers

    What is the role of the catalyst in the Haber’s process?

    <p>To decrease the activation energy</p> Signup and view all the answers

    What is the overall reaction in the oxidation of carbon monoxide using transition metal oxides?

    <p>2CO + O2 → 2CO2</p> Signup and view all the answers

    What type of oxides are used in dehydration reactions?

    <p>Acidic oxides</p> Signup and view all the answers

    What is the role of vanadium(V) oxide in the contact process?

    <p>To convert sulphur dioxide into sulphur trioxide</p> Signup and view all the answers

    What is the characteristic of p-type metal oxides?

    <p>Excess positive charges in the solid</p> Signup and view all the answers

    What is the function of molybdenum disulfide in low sulfur fuels?

    <p>To facilitate the removal of sulphur</p> Signup and view all the answers

    What is the type of catalyst used in the oxidation of carbon monoxide?

    <p>Heterogeneous catalyst</p> Signup and view all the answers

    What is the role of basic oxides in catalysis?

    <p>To favor reactions involving anionic species</p> Signup and view all the answers

    What is the purpose of the contact process?

    <p>To manufacture sulphuric acid</p> Signup and view all the answers

    According to the theory of activated complex, what determines the overall rate of catalytic reaction?

    <p>The rate of dissociation of the active complex into the final product</p> Signup and view all the answers

    What is the expression for the overall rate of reaction according to the steady state theory?

    <p>d[P]/dt = K1 K3 [A] [B] [C] / (K2 + K3 [B])</p> Signup and view all the answers

    What is the relationship between the rate of catalytic process and the concentration of reactants and catalyst?

    <p>The rate is directly proportional to the concentration of both reactants and catalyst</p> Signup and view all the answers

    What is the condition for the Arrhenius approach?

    <p>K2 is much larger than K3</p> Signup and view all the answers

    What is the expression for [ABC] according to the steady state theory?

    <p>[ABC] = (K3 / K4) [AC] [B]</p> Signup and view all the answers

    What is the experimental example of the Arrhenius type reaction?

    <p>Oxidation of thiosulphate with H2O2 using molebdenic acid as catalyst</p> Signup and view all the answers

    What is the rate of reaction in the Arrhenius approach?

    <p>Rate of reaction = [A] [B] [C]</p> Signup and view all the answers

    What is the intermediate complex formed in the catalytic reaction?

    <p>AC</p> Signup and view all the answers

    Study Notes

    Kinetic Treatment of Catalytic Homogeneous Reactions

    • The overall rate of catalytic reaction is determined by the rate of dissociation of the active complex into the final product.
    • The rate of activated complex formation can be represented as d[ABC]/dt = K3[AC][B] - K4[ABC] = 0.
    • The rate of formation of intermediate AC can be given as d[AC]/dt = K1[A][C] - K2[AC] - K3[AC][B] = 0.
    • The overall rate of reaction is represented as d[P]/dt = (K1K3[K2 + K3[B]][A][B][C].

    Approaches to Catalytic Reactions

    • Arrhenius approach: rate constant K2 is much larger than K3, so the rate of reaction is proportional to [A][B][C].
    • Van't Hoff approach: rate constant K3 is much larger than K2, so the rate of reaction is proportional to K1[A][C].

    Heterogeneous Catalysis

    • Heterogeneous catalysis involves a catalyst and reaction mixture in different phases.
    • Examples of heterogeneous catalysis include:
      • Hydrogenation of carbon-carbon double bond using nickel as a catalyst.
      • Methanol synthesis using copper/zinc oxide catalyst.
      • Catalytic converters using platinum, palladium, and rhodium to convert carbon monoxide and nitrogen oxides into carbon dioxide and nitrogen.
      • The use of vanadium(V) oxide in the contact process for manufacturing sulfuric acid.
      • Oxidation of carbon monoxide using transition metal oxides such as nickel oxide.
      • Acidic oxides (dehydration process) such as Al2O3 and SiO2.
      • Basic oxides (dehydrogenation process) such as MgO and ZrO.
      • Low sulfur fuels: desulfurization catalysis using molybdenum disulfide.

    Comparing Activation Energies

    • The decomposition of hydrogen peroxide:
      • Uncatalysed: 75 kJmol-1
      • Catalysed with colloidal platinum: 49 kJmol-1
      • Catalysed by the enzyme: 23 kJmol-1
    • The decomposition of hydrogen iodide:
      • Uncatalysed: 183 kJmol-1
      • Au catalysed: 105 kJmol-1
      • Pt catalysed: 58 kJmol-1
    • The synthesis of ammonia (Haber's process):
      • Uncatalysed: 350 kJmol-1
      • Transition metal tungsten (W) catalyst: 162 kJmol-1

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    Description

    This quiz covers the kinetic treatment of catalytic homogeneous reactions, including the role of activated complex theory in determining the overall rate of reaction.

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