UPSC Combined Geo-Scientist
Chemist
- 3 descriptive papers
- 200 marks each
- 3 h per paper
Mains Paper III covers analytical and organic chemistry.
All topics
Mains Paper III, analytical and organic chemistry
Inductively coupled plasma spectroscopy: every question, 2016 to 2025
16 parts worth 100 marks have been set on this unit in UPSC Geo-Scientist Chemistry Mains Paper III from 2016 to 2025. Each one opens on its own page with the question, the answer in brief and the key points.
Syllabus
Theory and principles, plasma generation, utility of peristaltic pump, sampler–skimmer systems, ion lens, quadrupole mass analyzer, dynode / solid state detector, different types of interferences: spectroscopic and non-spectroscopic interferences, isobaric and molecular interferences, applications.
Notes: X-ray methods (XRD, XRF) and ICP-OES / ICP-MS (full notes) · short notes
2025
- Q1(f) Quadrupole mass analyser in ICP–MS5 marks Answered
- Q4(b) Interferences in ICP–MS and their elimination10 marks Answered
2024
- Q1(f) Generation of the plasma in the ICP torch5 marks Answered
- Q1(h) AAS and ICP compared: accuracy, interferences, detection limit5 marks Answered
- Q3(b) Components of the ICP; the sampler–skimmer interface10 marks Question only
2023
- Q1(g) Interference of calcium in the ICP–MS determination of iron5 marks Answered
- Q5(b) Analysis of a solid sample by ICP–MS: sequence of steps10 marks Answered
2022
- Q1(g) Generation of the argon plasma in ICP–MS5 marks Answered
2021
- Q1(f) Why the ICP is an important source for emission spectroscopy5 marks Answered
- Q5(d) Peristaltic pump in ICP spectroscopy5 marks Answered
2020
- Q1(f) Sample introduction into ICP5 marks Answered
- Q3(c) Why plasma sources are preferred over flames5 marks Question only
2019
- Q5(b) Isobaric interferences in ICP-MS5 marks Question only
2018
- Q1(f) ICP multielement capability5 marks Answered
2017
- Q1(h) ICP-MS dilution calculation5 marks Answered
- Q3(d) Principle of ICP-MS; why avoid high salt content10 marks Question only
Printed copy and Kindle
UPSC Combined Geo-Scientist (Main) Chemistry Paper III: Model Answers 2021 to 2025
- All ten questions of each paper, with the question printed above its answer
- Instruments drawn as labelled diagrams, numericals worked with units
- Topic-wise weightage and a topic-wise index