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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 · Q21 of 120

Geo-Scientist Prelims 2026 Chemistry Q21: Sodium chloride reacts with sodium vapour to give a…

QuestionSolid state / metal excess defect

Sodium chloride reacts with sodium vapour to give a non-stoichiometric compound Na₁₊δCl. This leads to

  1. (a) Frenkel defect
  2. (b) Schottky defect
  3. (c) F center
  4. (d) Wadsley effect

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