Long Answer TypeThe accumulation of molecular species
at the surface rather than in the bulk of a solid or liquid is termed adsorption. The molecular species or substance, which concentrates or accumulates at the surface is termed adsorbate and the material on the surface of which the adsorption takes place is called adsorbent.
|
ADSORPTION |
ABSORPTION |
| It is surface phenomenon i.e. it occurs only at the surface of the adsorbent. | It is bulk phenomenon i.e. it occurs throughout the body of the material. |
| In this phenomenon, the concentration on the surface of adsorbent is different from that in the bulk. | In this phenomenon, the concentration is same throughout the material. |
| Its rate is high in the beginning and then decreases till equilibrium is attained. | Its rate remains same throughout the process. |
(i) Explain the meaning of the statement. ‘Adsorption is a surface phenomenon.’
(ii) State two features of chemical adsorption which are not found in physical adsorption.
(iii) Explain the terms with suitable examples: (i) Gel, (ii) Aerosol and (iii) Hydrosol.
Short Answer TypeOut of BaCl2 and KCl, which one is more effective in causing coagulation of a negatively charged colloidal Sol? Give reason.
In reference to Freundlich adsorption isotherm, write the expression for adsorption of gases on solids in the form of an equation.
Based on the type of particles of dispersed phase, give one example each of associated colloid and multimolecular colloid.
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