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General Principles and Processes of Isolation of Elements — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistryGeneral Principles and Processes of Isolation of Elements3 Marks
Question
Write the principles of the following methods:
  1. Vapour phase refining.
  2. Zone refining.
  3. Chromatography.
✓

Answer

  1. Vapour phase refining: In this process, the impure metal is converted into its volatile compound, which is decomposed to obtain the pure metal. The basic requirements for the vapour phase refining are:
  1. The metal should form a volatile compound with an available reagent.
  2. The volatile compound should decompose easily so that pure metal should be recovered.
  1. Zone refining: This method is used for producing metal of high purity. Metal like germanium, gallium and indium are prepared by this method. This method is based on the principle that impurities are more soluble in melt than in the solid state of the metal.
  2. Chromatography: This is the method used for the separation and purification of elements. It can also be used for testing the purity of a compound. The principle behind the chromatography is that different components of a mixture are differently adsorbed on an adsorbent.

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