What is adsorption? What are the factors which affect adsorption?

Que.: What is adsorption? What are the factors which affect adsorption?

Ans.:

Adsorption: When a solid surface is brought in contact with a gas or liquid, molecules from the gas or liquid starts to collect at the surface of the solid. This phenomenon of a collection of gas or liquid molecules on the surface of the solid is known as adsorption. A substance which accumulates on the solid surface as known as adsorbate and the solid surface on which it occurs is known as an adsorbent.

Factors affecting adsorption:

Factors affecting adsorption are given by-

1. Nature of adsorbent

2. Surface area

3. Nature of the gas

4. Exothermie nature

5. Pressure.

1. Nature of Adsorbent:

In general, if a gas is more liquefiable it will be more easily absorbed. For example, gases like NH4, , HCI, Cl2, CO2, which can be liquefied easily are more readily adsorbed on the solids surface rather than permanent gases like 02, H2 etc.

2. Surface Area:

When we increase the surface area of the adsorbent there is an increase in the adsorption of gases. This is because when we increase the surface area there is more number of adsorbing sites. So finely divided solids and some porous substances are good adsorbents.

3. Nature of the gas:

In general, if a gas is more liquefiable it will be more easily absorbed. For example, gases like NH4, HCI, Cl2, CO2, which can be liquefied easily are more readily adsorbed on the solids surface rather than permanent Bases like O2, H2 etc.

4. Exothermic nature:

The heat of adsorption can be defined as he energy liberated when 1 g mol of a gas is liberated on a solid surface.

Que.: What is adsorption? What are the factors which affect adsorption?