Question

What is the mechanism of adsorption?

Answer 1

1. Adsorption is the surface phenomenon that means the molecules are accumulated on the surface.
2. The surface on which the phenomenon takes place is called adsorbate and the molecular species are called adsorbents.
3. The process is exothermic because of the release of energy.
4. Enthalpy of adsorption is defined as the amount of energy released during adsorption when one mole of adsorbate is adsorbed on the adsorbent.
5. The enthalpy of adsorption is negative because the entropy decreases.
6. Enthalpy of adsorption is negative because the randomness of the molecules will be restricted.
7. Adsorption is a spontaneous process, which occurs at constant temperature and pressure.
8. Clay, silica gel, and colloids are common examples of adsorbents.
9. Below showing you the picture of adsorption:
   

Mechanism-

• Adsorption occurs when the particle on the surface and the particle in the adsorbent’s bulk are not in the same environment.
• Unbalanced forces, also known as residual attractive forces, act on the particle on the surface.
• Due to these forces, the adsorbent’s surface particles attract the adsorbate particles.
• Adsorption always results in a decrease in the surface’s residual attractive forces.
• That is, the surface’s energy decreases, and this is expressed as heat, which is known as the heat of adsorption.
• The enthalpy change is denoted as negative because when adsorbate molecules are adsorbed on the surface, their freedom of movement is restricted, resulting in a decrease in entropy.