Quick Recap — Choosing the Right Technique

  • Solid, soluble impurity →\to crystallisation; sublimable solid →\to sublimation.
  • Miscible liquids, close b.p. →\to fractional distillation; heat-sensitive liquid →\to reduced-pressure distillation; steam-volatile →\to steam distillation.
  • Colourless mixtures/pigments →\to chromatography.
  • Detect N/S/halogen by Lassaigne's; estimate by the appropriate quantitative method (Liebig, Dumas/Kjeldahl, Carius).