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UPSC Combined Geo-Scientist

Chemist

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

Mains Paper II covers physical chemistry.

UPSC Combined Geo-Scientist, Mains · 2016 · Mains Paper II

Q5. Parallel first-order reactions

Question

For parallel reactions A →(k₁) B and A →(k₂) C, derive concentrations as functions of time and represent them graphically.

Answer in brief

With [A]₀=A₀, [B]₀=[C]₀=0 and k=k₁+k₂: [A]=A₀e⁻ᵏᵗ, [B]=A₀k₁(1-e⁻ᵏᵗ)/k and [C]=A₀k₂(1-e⁻ᵏᵗ)/k.

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CoversParallel first-order reactionsChemical kinetics