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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 · 2023 · Paper I

Q6(a). Initial-rate analysis

Question

For 2A(g) + 2B(g) → C(g) + 2D(g) at 1000 °C, the initial-rate data are: [A] = 0.004, 0.008, 0.008 M; [B] = 0.0015, 0.0015, 0.0030 M; rates = 1.2 × 10⁻⁵, 4.8 × 10⁻⁵, 9.6 × 10⁻⁵ M/s, respectively. Determine (i) the rate law, (ii) the rate constant and (iii) the rate when [A] = 12.0 × 10⁻³ M and [B] = 6.0 × 10⁻³ M.

Answer in brief

r = k[A]²[B], k = 500 L² mol⁻² s⁻¹ and the new rate is 4.32 × 10⁻⁴ mol L⁻¹ 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 →

Coversinitial rate methodrate laworder of reactionrate constantthird-order kinetics

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