Emulsions can be diluted with any amount of the dispersion medium. On the other hand, the dispersed liquid when mixed, forms a separate layer.

The Freundlich adsorption isotherm is mathematically represented as $$\frac{x}{m} = k{P^{\frac{1}{n}}}$$
$$\eqalign{ & {\text{at high pressure}}\,\,\frac{1}{n} = 0.\,\,{\text{Hence}},\,\,\frac{x}{m} \propto {P^ \circ } \cr & {\text{at low pressure}}\,\,\frac{1}{n} = 1\,\,{\text{Hence}},\,\,\frac{x}{m} \propto P' \cr} $$

The water obtained from natural sources often contains suspended impurities. Alum is added to such water to coagulate the suspended impurities and make water fit for drinking purposes.

Fog is a colloidal solution of liquid in a gas, in which liquid is the dispersed phase whereas gas is the dispersion medium. Examples of other options are as follows:
Gas in liquid : Shaving cream, soda water, froth
Solid in gas : Dust in air
Gas in gas : Atmospheric air.

Peptization involves conversion of freshly prepared precipitate into colloidal particles using a suitable electrolyte.

The first layer of ions is firmly held and is termed as fixed layer while the second layer is mobile or diffused layer according to Helmholtz electrical double layer. The potential difference between fixed and diffused layer is called electrokinetic potential or zeta potential.

In colloidal solution the particles are suspended and are more dispersed than powdered form hence adsorption is maximum.

Sol is a type of colloid in which solid substance is dispersed phase and liquid is dispersion medium.

The efficiency of coagulation of an electrolyte depends upon its valency. Thus, $${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{4 - }}$$   is the best coagulating agent for $$Fe{\left( {OH} \right)_3}$$   sol.

Heat of adsorption of physical adsorption is quite low.