Question

Types of Adsorption?explain

Answer 1

Answer:

Explanation:

There are two types of Adsorption – Physical Adsorption or Physiosorption and Chemical Adsorption or Chemisorption.

Physical Adsorption

It involves adsorption of gases on solid surface via weak van der Waal’s forces.

Characteristics of Physical Adsorption

• There is no specificity in case of physical adsorption. Every gas is adsorbed on the surface of the solid.
• Nature of the adsorbate. Easily liquefiable gases are strongly adsorbed physically.
• Physical adsorption is reversible in nature. If pressure is increased volume of gas decreases as a result more gas is adsorbed. So, by decreasing the pressure, gas can be removed from the solid surface. Low temperature promotes physical adsorption and high temperature decreases the rate of adsorption.
• More surface area more is the rate of adsorption. Porous substances and finely divided metals are good adsorbents.
• Physical adsorption is an exothermic process.
• No activation energy is needed.

Chemical Adsorption or Chemisorption

When the gas molecules or atoms are held to the solid surface via chemical bonds, this type of adsorption is chemical adsorption or chemisorption.

Characteristics of Chemical Adsorption

• This type of adsorption is specific as compared to physical adsorption. Adsorption occurs only if there is formation of chemical bonds between the adsorbate and adsorbent.
• Chemical adsorption is irreversible.  It is an exothermic process but the process occurs slowly at low temperature. Chemisorption is accompanied by increase in temperature. High pressure promotes chemisorption.
• Chemisorption increases with increase in surface area.
• Due to chemical bond formation enthalpy of chemisorption is high.
• Activation energy is needed.
• It results in unimolecular layer.

Answer 2

Explanation:

Depending upon the nature of the forces involved, two main types of adsorption process may be distinguished, Page 2 1) Physical adsorption or the Physisorption 2) Chemical adsorption or Chemisorption The third type of adsorption, which is referred to, as activated adsorption

Hope This Will help you to