Combined Geo-Scientist Main 2021 Chemistry Paper III Question Paper PDF

Central Government Jobs Other Jobs 2021

  • Year 2021
  • Conducted By UPSC
  • Questions 10
  • Maximum Marks 200
  • Duration Three Hours
  • Languages English

Exam Details

Detail Information
Examination Combined Geo-Scientist (Main) Examination
Year 2021
Conducting Body UPSC
Paper Paper - III
Subject CHEMISTRY
Duration Three Hours
Maximum Marks 200
Number of Questions 10
Question Type Mixed

This document contains the official question paper for the Combined Geo-Scientist (Main) Examination 2021, Paper III, conducted by UPSC. The paper is for the subject of Chemistry and has a maximum mark of 200, with a time limit of three hours. It consists of 10 questions divided into two sections, requiring candidates to attempt six questions in total, including compulsory questions from each section. This paper is crucial for aspirants preparing for the Geo-Scientist examination, offering insights into the types of questions, marking scheme, and subject coverage.

Major Topics Covered

  • Chemistry
  • Analytical Chemistry
  • Spectroscopy
  • Chromatography
  • Gravimetric Analysis
  • Solvent Extraction
  • Coal Analysis

Why This Paper is Important

  • Useful for Combined Geo-Scientist (Main) Examinatio 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

  • Combined Geo-Scientist (Main) Examination 2020 Chemistry Paper III
  • Combined Geo-Scientist (Main) Examination 2022 Chemistry Paper III
  • Combined Geo-Scientist (Preliminary) Examination 2021 Chemistry Paper I
  • Combined Geo-Scientist Main 2021 Chemistry Paper III Answer Key
  • Combined Geo-Scientist Main Chemistry Syllabus
  • UPSC Chemistry Syllabus for Main Exam
  • Combined Geo-Scientist Main Exam Pattern
  • UPSC Geo-Scientist Main Exam Structure

Instructions

  • There are TEN questions divided under TWO sections.
  • Candidate has to attempt SIX questions in all.

Questions (page 2)

Section A

Q1.

(a) The following values were obtained for the determination of cadmium in a sample of dust: 4.3, 4.1, 4.0 and 3.2 ,mu g ,g^{-1}
Applying the Q-test, decide whether the last value, 3.2, should be rejected or not. [Given : Q critical for a sample size of four is 0.831]

(b) What is the ultimate analysis of coal?

(c) A solution of concentration 1 × 10-3 M shows 60% transmittance where the cell thickness is 1 cm. Calculate the molar absorptivity of the sample solution. [Given : log10 (0.60) = -0.2218]

(d) How will you estimate Zn in brass gravimetrically?

(e) Mention the requisite conditions of the extracting solvent to be fit for solvent extraction.

(f) "Inductively Coupled Plasma (ICP) source is important as an atomisation source for emission spectroscopy." Explain why.

(g) Mention the function of Hollow Cathode Lamp (HCL). How does it function?

(h) "X-ray powder diffraction methods are well-suited for solid state qualitative identification." Explain why.

Section A

Q2.

(a) What do you mean by Rf (retardation factor) as used in Thin Layer Chromatography (TLC)? What is the unit of Rf? On which factor(s) does this Rf value depend(s)? What is the utility of this factor?

(b) 5 gm sample of brass is dissolved in acid and the volume is made up to 250 mL to prepare a stock solution. 25 mL of this stock solution is pipetted out and is titrated iodometrically with 0. 1010 N standard \textNa2\textS2\textO3 solution to have 16 mL titre value. Calculate the % Cu in the brass sample. [Atomic weight of Cu = 63. 54].

(c) What is the main infrared (IR) region of interest for analytical purposes? Write down the main sources of IR radiation as used in IR spectrophotometers. Which is the main means of monochromation in the IR region and why? Mention the detectors as used in the detection of IR signal.

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Frequently asked questions

What is the name of the examination?

The examination is the Combined Geo-Scientist (Main) Examination.

Which year is this question paper for?

This question paper is for the year 2021.

Who conducts the Combined Geo-Scientist Examination?

The examination is conducted by UPSC (Union Public Service Commission).

What is the subject of Paper III?

Paper III is for the subject of CHEMISTRY.

What is the maximum marks for this paper?

The maximum marks for Paper III is 200.

What is the time duration allowed for this paper?

The time allowed for this paper is Three Hours.

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