SURFACE
CHEMISTRY
PART-1
ADSORPTION
, Introduction :
• Surface chemistry deals with phenomena that occur at the surfaces or
interfaces.
,Meaning of adsorption:
The accumulation of molecular species at the surface rather than in the bulk of a solid or liquid is
termed adsorption.
Adsorbate and adsorbent :
The molecular species or substance, which concentrates or accumulates at the surface is termed
adsorbate and the material on the surface of which the adsorption takes place is called adsorbent.
Eg charcoal , silica gel, alumina gel, clay, colloids, metals in finely divided state, etc. act as good
adsorbents.
, Adsorption in action :
1. If a gas like O2, H2, CO, Cl2, NH3 or SO2 is taken in a closed vessel containing powdered
charcoal, it is observed that the pressure of the gas in the enclosed vessel decreases.
2. In a solution of an organic dye, say methylene blue, when animal charcoal is added and the
solution is well shaken, it is observed that the filtrate turns colourless.
3. The air becomes dry in the presence of silica gel because the water molecules get adsorbed
on the surface of the gel.
CHEMISTRY
PART-1
ADSORPTION
, Introduction :
• Surface chemistry deals with phenomena that occur at the surfaces or
interfaces.
,Meaning of adsorption:
The accumulation of molecular species at the surface rather than in the bulk of a solid or liquid is
termed adsorption.
Adsorbate and adsorbent :
The molecular species or substance, which concentrates or accumulates at the surface is termed
adsorbate and the material on the surface of which the adsorption takes place is called adsorbent.
Eg charcoal , silica gel, alumina gel, clay, colloids, metals in finely divided state, etc. act as good
adsorbents.
, Adsorption in action :
1. If a gas like O2, H2, CO, Cl2, NH3 or SO2 is taken in a closed vessel containing powdered
charcoal, it is observed that the pressure of the gas in the enclosed vessel decreases.
2. In a solution of an organic dye, say methylene blue, when animal charcoal is added and the
solution is well shaken, it is observed that the filtrate turns colourless.
3. The air becomes dry in the presence of silica gel because the water molecules get adsorbed
on the surface of the gel.
