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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 · 2023 · Mains Paper III

Q5(d). Aniline point and Doctor test of petroleum products

Question

What information is obtained in the analysis of petroleum product by Aniline point and Doctor test, respectively?

Answer in brief

Aniline point: the aromatic content (low = aromatic, high = paraffinic), hence diesel ignition quality and action on rubber. Doctor test: whether mercaptans (and H₂S) are present, i.e. whether the product is sour or sweet.

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The full model answer

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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 →

Coversaniline pointDoctor testmercaptansdiesel indexpetroleum analysissour and sweet

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