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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

Q5(a). Order from total-pressure measurements

Question

For ClCO₂CCl₃(g) → 2 COCl₂(g) at 290 °C and constant volume, t/s = 0, 181, 513, 1164 and total P/mmHg = 15.76, 18.88, 22.79, 27.08. Determine the order and rate constant graphically.

Answer in brief

The data are approximately first order, with k ≃ 1.1 × 10⁻³ s⁻¹.

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Topic notes: rate laws, integrated rate equations and half-lives, with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversfirst-order reactiontotal pressure methodrate constant graphicallyintegrated rate lawtrichloromethyl chloroformate decomposition

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