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Absorption |
Adsorption |
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1. It is the phenomenon in which the particles of gas or liquid get uniformly distributed throughout the body of the solid. 2. The concentration is the same through the material. Therefore, it is a bulk phenomenon. 3. Absorption occurs at uniform rate. |
1. It is the phenomenon of higher concentra-tion of particles of gas or liquid on the surface than in the bulk of the solid. 2. The concentration on the surface of the adsorbent is different from that in the bulk. Therefore, it is a surface phenomenon. 3. Adsorption is rapidly in the beginning and its rate slowly increases. |
Example of adsorption: NH3, adsorbed by charcoal, H2O adsorbed by silica, ink adsorbed by chalk.
Example of absorption: NH3 absorbed by water, water absorbed by anhydrous CaCl2, water absorbed by a sponge.
Explain the following observations:
(a) Cottrell’s smoke precipitator is fitted at the mouth of the chimney used in factories.
(b) Physical adosption is multi layered, while chemisorption non-tayered.
