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UPSC Geo-Scientist and Geologist Exam Papers 2019 : Chemistry Paper - III

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Exam Name : UPSC Geo-Scientist and Geologist Exam 2019

Subject : Chemistry Paper - III

Year : 2019

CHEMISTRY
Paper - III

ITime Allowed : Three Hours

Maximum Marks : 200

QUESTION PAPER SPECIFIC INSTRUCTIONS

SECTION 'A'

1. Answer all of the following questions : 5x8=40

(a) Rewrite the following statement(s) if you find it/them incorrect : Over the ionic strength range 0-01 M

(i) activity coefficients increase with increasing ionic strength;
(ii) activity coefficients increase with increasing ionic charge.

(b) The molarity of C₂₉H₆₀ in winter rainwater is 5-6 nm. Find its concentration in parts per billion (ppb).

(c) You have been asked to prepare a buffer solution with an alkaline pH by mixing ammonium chloride and aqueous ammonia from the following sets of solutions :

(i) 50 ml solutions of 0.001 molar NH₄Cl and 0.003 molar aqueous ammonia
(ii) 50 ml solutions of 0.1 molar NH₄Cl and 0-3 molar aqueous ammonia Will both of them work? If not, which one will work efficiently and why?

(d) During an acid-base titration experiment, a student noticed some drops of acid on the inside of the neck of the conical flask. The student decided to wash the drops into the main solution using distilled water. Briefly explain whether the action will have any consequences on the outcome of the titration.

(e) In flame photometry, the analysis of analyte is carried out only in an interzonal region of the flame but not in the outer cone or primary combustion zone of the flame. Justify.

(f) Explain the proximate analysis of coal.

(g) How do you estimate manganese present in a steel sample volumetrically?

(h) What is a gradient elution development in chromatography?