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UPSC Combined Geo-Scientist

Chemist

  • 3 descriptive papers
  • 200 marks each
  • 3 h per paper

Mains Paper III covers analytical and organic chemistry.

UPSC Combined Geo-Scientist, Mains · 2021 · Mains Paper III

Q2(b). Copper in brass by iodometric titration

Question

2.5 g 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 Na₂S₂O₃ solution to have 16 mL titre value. Calculate the % Cu in the brass sample. [Atomic weight of Cu = 63.54]

Answer in brief

Cu = 41.07 % (about 41.1 %).

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Topic notes: analysis of ores, alloys, petroleum, coal and coke (dolomite, bauxite, brass, Ni in steel, aniline point, proximate and ultimate analysis, calorific value), with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversiodometric titrationcopper in brasssodium thiosulfatevolumetric estimation

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