Surface Chemistry

Gold number is the measure of protective power of lyophilic colloid. [Higher the value of gold number, lower will be the protective power]

Easily liquifiable gas gets adsorbed readily over the activated charcoal.
The order of ease of liquification of given gases is

is adsorbed most readily by activated charcoal.

At lower pressure, the graph is nearly straight and sloping, i.e.,

or constant
At high pressure, becomes independent of value of pressure.

or constant
In the intermediate range of pressure, will depend on raised to powers between and , i.e., fractions.

or constant

In general easily liquefiable gases (with higher critical temperatures) are readily adsorbed, so is adsorbed to a larger extent on charcoal.

Haemoglobin (blood) is the positively charged Gold sols, clay and are the examples of negatively charged sols.

If the chemical forces hold the gas molecules to the surface of the adsorbent, the adsorption is termed as chemical adsorption (chemisorption). Chemisorption is irreversible.