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Indian Forest Service (Mains)

Chemistry optional

  • 2 papers
  • 200 marks each
  • 3 h per paper

Paper I covers physical and inorganic chemistry.

Indian Forest Service (Mains), Chemistry optional · 2025 · Paper I

Q6(a)(i). Ozone decomposition

Question

For M + O₃ ⇌ O₂ + O + M (k₁, k₋₁), followed by O + O₃ → 2 O₂ (k₂), derive the rate of ozone disappearance using the steady-state approximation.

Answer in brief

−d[O₃]/dt = 2k₁k₂[M][O₃]²/(k₋₁[M][O₂] + k₂[O₃]).

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Topic notes: Arrhenius equation, collision theory and transition-state theory, with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversozone decomposition mechanismsteady-state approximationrate law derivationthird body M

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