Class 12 Chemistry Surface Chemistry Factors affecting adsorption of Gases by Solids

Factors affecting adsorption of Gases by Solids

  • Nature and Surface area of adsorbent:
    • The same gas is adsorbed by different solids at different extents even at the same temperature.
    • Greater the surface area, greater is the volume of gases adsorbed.
  •  Nature of the gas being adsorbed:
  • Different gases are adsorbed are adsorbed to different extents even by the same solid.
  • As the critical temperature of a gas increases, it is easier to liquefy and it is also more readily adsorbed.
  • Reason- Higher the critical temperature, the easier it is to liquefy the gas as greater are the intermolecular forces to attraction between the molecules of the gas. For such a gas, the intermolecular forces of attraction are greater on the surface of the adsorbent and thus, the adsorption will be more.
  • Temperature: As temperature increases, adsorption decreases
  • Pressure: At constant temperature, the adsorption of a gas increases with increase in pressure.
  • Activation of the solid adsorbent: It means increasing the adsorbing power of the adsorbent.

It can be done by-

  1. Making the surface of the adsorbent rough- It can be done by rubbing the surface or chemical action or by depositing fine metal particles on the surface by electroplating
  2. By dividing the adsorbent into small pieces or grains- It increases the surface area but this method has a practical limitation. If the particles are too fine like powder, the adsorption of the gas will become difficult.
  3. By removing the already adsorbed gases

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