UPSC Combined Geo-Scientist
Chemist
- 3 descriptive papers
- 200 marks each
- 3 h per paper
Mains Paper II covers physical chemistry.
All years
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Mains Paper II, physical chemistry
Question paper, 2025
UPSC Combined Geo-Scientist, Stage II (Mains). 7 pages, as issued by UPSC.
Every question of 2025, one page each36 parts in 15 questions, with the question as text and the key points of its answer
Question 1 80 marks
- 1(a)Why Z > 1 for H₂ and He at all pressures5 marks
- 1(b)Corresponding state of H₂S for N₂ at 25 °C and 1 atm5 marks
- 1(c)Band structure of n-type and p-type semiconductors5 marks
- 1(d)Symmetry elements of orthorhombic Mg₂SiO₄5 marks
- 1(e)Fall of G with temperature at constant pressure5 marks
- 1(f)Z > 1 and f > P for the gas P(Vm − b) = RT5 marks
- 1(g)Overall equation and the role of each species5 marks
- 1(h)log k against pH for specific H⁺ catalysis5 marks
- 1(i)KCl salt bridge for a silver–lead cell5 marks
- 1(j)Equilibrium constant from standard potentials5 marks
- 1(k)Conditions for an acceptable wave function5 marks
- 1(l)No solution with E = 0 for the particle in a box5 marks
- 1(m)Discrete levels and the resonance condition5 marks
- 1(n)Rotational activity of CO and CO₂5 marks
- 1(o)Measuring light intensity with a chemical actinometer5 marks
- 1(p)Why watch hands glow in the dark5 marks
Question 2 10 marks
Question 3 10 marks
Question 4 10 marks
Question 5 10 marks
Question 6 10 marks
Question 7 10 marks
Question 8 10 marks
Question 9 10 marks
Question 10 10 marks
Question 11 20 marks
Question 12 20 marks
Question 13 20 marks
Question 14 20 marks