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UPSC Civil Services (Mains)

Chemistry optional

  • 2 papers
  • 250 marks each
  • 3 h per paper
  • 5 of 8 questions, Q1 and Q5 compulsory

Paper I covers physical and inorganic chemistry.

UPSC Civil Services (Mains), Chemistry optional · 2021 · Paper I

Q8(a). BrF₃ as an aprotic solvent: acids, bases and neutralisation

Question

Justify that the interhalogen compound BrF₃ acts as an aprotic solvent and undergoes acid-base and neutralization reactions by giving examples.

Answer in brief

BrF₃ has no hydrogen (aprotic), yet it ionises itself, 2 BrF₃ ⇌ [BrF₂]⁺ + [BrF₄]⁻; acids (SbF₅) give [BrF₂]⁺, bases (KF) give [BrF₄]⁻, and together they give a salt and BrF₃.

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Topic notes: non-aqueous solvents: liquid ammonia, HF, sulfuric acid, SO₂, BrF₃ and superacids, with every Civil Services, IFoS and Geo-Scientist PYQ →

CoversBrF3 solventsolvent system conceptnon-aqueous solventsself-ionisationinterhalogen compounds

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