UPSC Combined Geo-Scientist
Chemist
- 3 descriptive papers
- 200 marks each
- 3 h per paper
Mains Paper III covers analytical and organic chemistry.
All years
Page 1 of 8 
Page 2 of 8 
Page 3 of 8 
Page 4 of 8 
Page 5 of 8 
Page 6 of 8 
Page 7 of 8 
Page 8 of 8
Mains Paper III, analytical and organic chemistry
Question paper, 2021
UPSC Combined Geo-Scientist, Stage II (Mains). 8 pages, as issued by UPSC.
Every question of 2021, one page each43 parts in 10 questions, with the question as text and the key points of its answer
Question 1 40 marks
- 1(a)Q-test on four results for cadmium in dust5 marks
- 1(b)Ultimate analysis of coal5 marks
- 1(c)Molar absorptivity from the transmittance5 marks
- 1(d)Gravimetric estimation of zinc in brass5 marks
- 1(e)Requirements of an extracting solvent5 marks
- 1(f)Why the ICP is an important source for emission spectroscopy5 marks
- 1(g)Hollow-cathode lamp: function and working5 marks
- 1(h)Powder X-ray diffraction for identifying solids5 marks
Question 2 30 marks
Question 3 30 marks
Question 4 30 marks
Question 5 30 marks
Question 6 40 marks
- 6(a)Reactivity of four alkenes towards electrophilic addition4 marks
- 6(b)Quaternisation, then Sommelet–Hauser rearrangement4 marks
- 6(c)Woodward–Fieser rules: three dienones4 marks
- 6(d)Carbonyl stretching bands of three lactones4 marks
- 6(e)Epoxidation of cholesterol with a peroxy acid4 marks
- 6(f)Norrish Type II reaction of two aryl alkyl ketones6 marks
- 6(g)Three isomeric esters C₄H₈O₂ from ¹H NMR6 marks
- 6(h)McLafferty rearrangement in a ketone, an acid and an ester6 marks
- 6(i)Stretching frequencies of six single bonds2 marks
Question 7 30 marks
Question 8 30 marks
Question 9 30 marks