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
Errors in quantitative analysis: every question, 2016 to 2025
15 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
Accuracy and precision, sensitivity, specific standard deviation in analysis, classification of errors and their minimization, significant figures, criteria for rejection of data, Q-test, t-test and F-test, control chart, sampling methods, sampling errors, standard reference materials, statistical data treatment.
Notes: Errors in chemical analysis: accuracy, precision, standard deviation, Q-test, t-test, F-test (full notes) · short notes
2025
- Q1(a) Sample mass for a sampling standard deviation of ±5 %5 marks Answered
- Q2(c) Q-test on five results for Fe in an iron ore5 marks Answered
2024
- Q1(a) Percentage relative error of a balance reading5 marks Answered
- Q5(a) Confidence interval of a mean at the 99 % level5 marks Answered
2023
- Q1(a) Relative standard deviation of replicate results5 marks Answered
- Q2(a) Type of analysis: 1 µL sample, analyte at ppb to ppm5 marks Question only
- Q5(c) Paired t-test: carbon in coal by two methods10 marks Answered
2022
- Q1(a) Accuracy and precision5 marks Answered
- Q5(a) New method against a reference method: F-test and t-test15 marks Answered
2021
- Q1(a) Q-test on four results for cadmium in dust5 marks Answered
- Q5(a) Accuracy and precision of two analysts; types of error10 marks Answered
2020
- Q1(a) Significant figures5 marks Answered
- Q2(a) Uncertainty in solubility5 marks Answered
- Q5(d) F-test and t-test: voltammetry versus FIA10 marks Question only
2016
- Q6(b) Pipette histogram and Gaussian5 marks Answered
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