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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 · 2026 · Mains Paper II

Q4. Gibbs–Duhem relations and the chemical potential

  • 10 marks
  • Topic: Thermodynamics
  • Question only
Question

The Gibbs–Duhem relations are (i) dG=Σᵢμᵢ dnᵢ, (ii) G=Σᵢnᵢμᵢ, (iii) 0=Σᵢnᵢ dμᵢ, for closed systems and at constant P and T. (I) Mention the nature of the system. (II) Derive the expression of μᵢ using eqn. (i). (III) Which one is an intensive property and why: μᵢ or G? (IV) What factors can influence the value of μᵢ?

Model answer

The free solution for 2026 answers the questions picked in its time plan. Question 4 is answered in full in the Book Edition of the 2026 solutions of Geo-Scientist Chemistry Paper II.

Read the 2026 solutionAbout the book

Coverschemical potentialGibbs–Duhem relations and the chemical potential

All parts of Question 4

  • 4 Gibbs–Duhem relations and the chemical potential10 marks