Column chromatography is one of the most useful methods for the separation and purification of both solids and liquids. This is a solid-liquid technique in which the stationary phase is a solid and the mobile phase is a liquid. The principle of column chromatography is based on differential adsorption of a substance by the adsorbent.

Soap is an emulsifying agent because the molecule has a hydrophilic end and a hydrophobic end.
The hydrophobic end dissolves in the oil base and the hydrophilic end dissolves in the water base; hence, soap helps to stabilise the emulsion.

A catalyst is specific in its action.

The following two factors are responsible for the increase in the rate of surface-catalysed reactions:
1. Heat of adsorption of reactants on a catalyst helps the reactant molecules to attain the required activation energy and overcome the energy barrier.
2. Adsorption increases the local concentration of the reactant molecules on the surface of the catalyst.

Blood is a colloidal solution. Its coagulation can be understood by Hardy-Schulze's law, which states that the higher the charge on the active ion, the higher its efficiency to coagulate the colloidal solution. In the present case, ferric chloride has Fe³⁺ ion. Hence, ferric chloride is more effective in enhancing the coagulation rate of blood and in stopping the bleeding from a cut.

The rate of oxidation of oxalic acid by acidified potassium permanganate increases as the reaction progresses. This acceleration is due to the presence of Mn²⁺ ions which are formed during the reaction. Thus, Mn²⁺ ions act as autocatalysts.

Physical adsorption can be reversed by increasing the temperature. So, it is a reversible process.

The efficiency of enzyme catalysis is due to its capacity to lower the activation energy of the reaction. Enzymes are biocatalysts which increase the rate of reaction without being consumed in the reaction. In case of equilibrium reactions, a catalyst helps in attaining equilibrium quickly without disturbing the equilibrium.

Metal sulphide is a hydrophobic substance, and will not form a lyophilic sol when added to water. Lyophilic sols are formed when there is a great affinity between the dispersion phase and the dispersion medium.

Presence of carbon monoxide poisons the iron catalyst in the Haber Process for the synthesis of ammonia.