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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 · 2023 · Paper I

Q8(b). Spin-only magnetic moments of four complexes

Question

Calculate the spin-only magnetic moment (μs.o.) of the central metal atom in the following complexes: (i) [Fe(H₂O)₅NO]²⁺; (ii) [Cr(NCS)₆]³⁻; (iii) [V(H₂O)₆]³⁺; (iv) [Co(bpy)₃]²⁺.

Answer in brief

(i) 3.87 BM; (ii) 3.87 BM; (iii) 2.83 BM; (iv) 3.87 BM.

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Topic notes: crystal field theory, with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversspin-only magnetic momentunpaired electronshigh spin low spinbrown ring complexcrystal field theory

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