Combined Geo-Scientist Chemistry Paper III 2025 (Main) – UPSC
- Year 2025
- Conducted By BGSP-C-CMS
- Questions 10
- Maximum Marks 200
- Duration Three Hours Maximum Marks: 200
- Languages English
Exam Details
| Detail | Information |
|---|---|
| Examination | Combined Geo-Scientist (Main) |
| Year | 2025 |
| Conducting Body | BGSP-C-CMS |
| Paper | Chemistry Paper – III |
| Subject | Chemistry |
| Duration | Three Hours Maximum Marks: 200 |
| Maximum Marks | 200 |
| Number of Questions | 10 |
| Question Type | Descriptive / Subjective |
This JSON aggregates page 1 and repaired page 2 OCR for Chemistry Paper III of the Combined Geo-Scientist (Main) Examination 2025. Page 1 provides exam metadata, time, marks, paper code, and language instructions (English). Page 2 contains repaired objective questions with multi-part stems covering sampling theory, van Deemter equation, UV-Vis, thermogravimetric analysis, ICP–MS, gravimetric nickel estimation, X-ray diffraction lattice spacing, and HPLC retention concepts. The data is structured to support SEO elements including FAQ, topics, tags, keywords, and image metadata for discovery while preserving numbering and line breaks as per the original OCR.
Major Topics Covered
- Analytical Chemistry
- Chromatography
- HPLC
- ICP-MS
- Mass Spectrometry
- Flame Photometry
- UV-Vis Spectrophotometry
- X-ray Diffraction
- Powder Diffraction
- Thermogravimetric Analysis
- Van Deemter Equation
- Sampling Theory
- Gravimetric Analysis
- Nickel in steel
- Cu K-alpha radiation
- Lattice Spacing
- 2Theta
- Sample Preparation
- Data Analysis
- Quantitative Methods
Why This Paper is Important
- Useful for Combined Geo-Scientist (Main) preparation
- Helps understand the latest exam pattern
- Useful for practice and self-assessment
- Covers frequently asked General Studies topics
- Helpful for analysing question trends
Related Resources
Instructions
- There are TEN questions divided under TWO sections.
- Candidate has to attempt SIX questions in all.
Questions (page 2)
Q1. Q1. From the following data, determine the mass of the sample that should be analyzed to obtain sampling standard deviation of ±5%.
Q1. Combined Geo-Scientist (Main) CONSEISTITION A From the following data, determine the mass of the sample that should Q1. (a) 5 be analyzed to obtain sampling standard deviation of ± 5\% Given Data Relative standard Sample mass (g) deviation (\%) 15 0.1 6 1.5 9.2
Q2.
5 Write the van Deemter equation and briefly discuss its significance. 5 (b) How can concentration of a non-absorbing analyte be measured by
(c) 5 UV-vis spectrophotometry? Show the flame absorption profiles for magnesium and silver with (d) 5 respect to flame height. Justify. What happens in the thermogravimetric analysis for the following (e) conditions? Higher furnace heating rate
(i) Larger particle size of sample
(ii) For sample undergoing endothermic reaction 5
(iii) 5 Explain the working principle of quadrupole mass analyzer in ICP–MS. (f) Briefly outline the gravimetric method for the estimation of nickel (g) 5 content in steel sample. The powder X-ray diffraction pattern (first order) of a metal is measured (h) with Cu – K a radiation source (λ = 1.539 Å). Calculate the lattice spacing of the material for diffraction measured at 2θ = 60\circ. 5 In an HPLC measurement, a solute has a retention time of 21·0 min and Q2. (a) an unretained species is eluted in 1.0 min using a mobile phase comprising 20% (vol by vol) methanol and 80% water. Determine the composition of methanol and water to elute the solute corresponding to retention factor 5.0. Given: Polarity index of water is 10.2, methanol is 5.1;
(i) log 2 = 0.301
(ii) 10
Q2.
5 Write the van Deemter equation and briefly discuss its significance. 5 (b) How can concentration of a non-absorbing analyte be measured by
(c) 5 UV-vis spectrophotometry? Show the flame absorption profiles for magnesium and silver with (d) 5 respect to flame height. Justify. What happens in the thermogravimetric analysis for the following (e) conditions? Higher furnace heating rate
(i) Larger particle size of sample
(ii) For sample undergoing endothermic reaction 5
(iii) 5 Explain the working principle of quadrupole mass analyzer in ICP–MS. (f) Briefly outline the gravimetric method for the estimation of nickel (g) 5 content in steel sample. The powder X-ray diffraction pattern (first order) of a metal is measured (h) with Cu – K a radiation source (λ = 1.539 Å). Calculate the lattice spacing of the material for diffraction measured at 2θ = 60\circ. 5 In an HPLC measurement, a solute has a retention time of 21·0 min and Q2. (a) an unretained species is eluted in 1.0 min using a mobile phase comprising 20% (vol by vol) methanol and 80% water. Determine the composition of methanol and water to elute the solute corresponding to retention factor 5.0. Given: Polarity index of water is 10.2, methanol is 5.1;
(i) log 2 = 0.301
(ii) 10
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Frequently asked questions
What is the exam name and year?
Combined Geo-Scientist (Main) Examination, 2025.
Which subject and paper is this?
Chemistry Paper – III.
How many questions are there and how many must be attempted?
There are ten questions. A total of six questions must be attempted.
Which questions are compulsory?
Question 1 in Section A and Question 6 in Section B are compulsory.
From which sections should you choose the remaining questions?
Choose two questions from Section A and two from Section B.
In which language must answers be written?
Answers must be written in English.