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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 · 2024 · Mains Paper II

Q4. Equilibrium constant and standard Gibbs energy change

Question

Obtain an expression for the equilibrium constant and standard free energy change using a general reversible reaction: aA + bB ⇌ cC + dD.

Answer in brief

At equilibrium ΔrG = ΔrG° + RT ln Q = 0 and Q = K: ΔrG° = −RT ln K, K = e−ΔrG°/RT.

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Topic notes: chemical equilibrium, ΔG° = −RT ln K, Kp, Kc, Kx and the van ’t Hoff equations, with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversvan 't Hoff reaction isothermΔG° = −RT ln Kequilibrium constantchemical potentialreaction quotient