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Organic Chemistry

Detection Of Halogens

Detection of halogens: Sodium halide is formed if the sodium extract contains halide. The extract is boiled with nitric acid (dilute) to decompose NaCN or Na2S (if present), if not a white ppt. of AgCN or Ag2S will be seen even if there is an absence of halogen. Finally, the solution is cooled, and AgNO3 is added to see characteristic ppt.

  • White ppt soluble in aq. Ammonia indicates chlorine.
  • Light yellow ppt. Sparingly soluble in aq. Ammonia indicates bromine.
  • Pale yellow ppt. Insoluble in aq. Ammonia indicates iodine