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UPSC Combined Geo-Scientist

Chemist

  • 2 objective papers
  • 120 questions each
  • 2 h per paper
  • 100 + 300 marks

Prelims Paper II covers chemistry.

UPSC Combined Geo-Scientist, Prelims · 2026 · Paper II, Chemistry · Q18 of 120

Geo-Scientist Prelims 2026 Chemistry Q18: The radius of Na⁺ ion is 0·95 Å and that of Cl⁻ ion is 1·81 Å. In…

QuestionSolid state / radius ratio

The radius of Na⁺ ion is 0·95 Å and that of Cl⁻ ion is 1·81 Å. In which one of the following sites Na⁺ ions will prefer to occupy in the crystal lattice of Cl⁻ ions ?

  1. (a) Plane trigonal
  2. (b) Tetrahedral
  3. (c) Octahedral
  4. (d) Body-centred cubic

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