Indian Forest Service (Mains)
Chemistry optional
- 2 papers
- 200 marks each
- 3 h per paper
Paper I covers physical and inorganic chemistry.
All years
Pages 1 and 2 of 28 
Pages 3 and 4 of 28 
Pages 5 and 6 of 28
Pages 7 and 8 of 28 Pages 9 and 10 of 28 Pages 11 and 12 of 28 Pages 13 and 14 of 28 Pages 15 and 16 of 28 Pages 17 and 18 of 28 Pages 19 and 20 of 28 Pages 21 and 22 of 28 Pages 23 and 24 of 28 Pages 25 and 26 of 28 Pages 27 and 28 of 28 
Paper I, physical and inorganic chemistry
Solution, 2025
Indian Forest Service (Mains), Chemistry optional. 28 pages. Questions 1, 2, 3, 5 and 6 are answered.
Every question of 2025, one page each42 parts in 8 questions, with the question as text and the key points of its answer
Question 1 40 marks
Question 2 40 marks
Question 3 40 marks
Question 4 40 marks
- 4(a)(i)Boiling point at reduced atmospheric pressure5 marks
- 4(a)(ii)Chemical potential of supercooled water5 marks
- 4(b)(i)Incongruent melting and azeotropy5 marks
- 4(b)(ii)Testing the stated activity-coefficient result10 marks
- 4(c)(i)Hydrogen and propane fuel cells10 marks
- 4(c)(ii)Competition between zinc deposition and hydrogen5 marks
Question 5 40 marks
Question 6 40 marks
Question 7 40 marks
Question 8 40 marks
Part of VKC Basic
Read the full model answer to every question of this paper with VKC Basic
VKC Basic (₹999 for 6 months) opens every solved answer, the notes, the handbook and the daily answer archive. Every Mains test series includes it.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Printed copy and Kindle
UPSC Indian Forest Service (Main) Chemistry Paper I: Model Answers 2021 to 2025
The book has all five years of Paper I in one volume, with all eight questions of every paper answered, the question printed above each answer, a time plan for each paper, the topic-wise weightage of marks and a topic-wise index.