Physical adsorption involves Van der Waals forces.

Chemical adsorptions permit only the formation of a monolayer af adsorbates on the adsorbent.

Chemical adsorption is easily reversible.

Adsorption is an endothermic process.

Complex structures are more easily adsorbed than simpler ones.

Adsorption processes proceed more rapidly at higher temperatures.

Increasing the surface area of the adsorbent increases the adsorption.

Adsorption isotherm is the process by which the adsorbate is adsorbed on the adsorbent as a function of its pressure (if gas) or concentration (if liquid) at constant temperature.

Freundlich isotherm provided a theoretical relationship between the amount of gas adsorbed by a unit mass of solid adsorbent and pressure at a particular temperature. 

Freundlich isotherm characterises physical adsorption.

At high temperature, Freundlich isotherm always seem to approach saturation.

Langmuir isotherm is also known as type I isotherm.

Type I isotherm characterises chemical adsorption.

Langmuir adsorption isotherm assumes that the adsorbed molecules interact with each other, as well as with the adsorbent molecules.

Langmuir adsorption isotherm assumes that the adsorption occurs through various different mechanisms.

The figure shows a

The figure shows a

The greater the surface area of the adsorbent, the lesser is the volume of gas adsorbed.

A gas is more liquefiable it will be less easily adsorbed.

Adsorption decreases with the increase of temperature.