how are colloids classified on the basis of size of the particle of dispersion phase
Answers
Answer:
The classification of colloids on the basis of (i) physical states of components:
On the basis of physical states of the dispersed phase and dispersion medium, the colloidal solutions classified into eight types of colloidal systems as shown in the following table.
Note: A mixture of gas with another gas is a homogeneous mixture and not a colloidal solution.
Dispersed phase
Dispersion medium
Type of colloidal solution
Example
Solid Solid
Solid sol
Alloys
Solid
Liquid Sol Paints
Solid Gas Aerosol Smoke
Liquid Solid Gel Jelly
Liquid
Liquid Emulsion Milk
Liquid Gas Aerosol Mist
Gas Solid Solid sol
Pumice
Gas
Liquid Foam Soap
(ii) Nature of dispersed phase and dispersion medium:
Colloids are classified into following.
(i) Alcosol
It is a colloidal solution of a solid (dispersed phase) in alcohol (Dispersion medium).
(ii) Aerosol
It is a colloidal solution of a liquid (dispersed phase) in gas (Dispersion medium). Example includes fog.
(iii) Hydrosol
It is a colloidal solution of a solid (dispersed phase) in water (Dispersion medium).
(iv) Benzosol :
It is a colloidal solution with benzene as dispersion medium.
(iii) Interaction between dispersed phase and dispersion medium:
Colloids are classified into lyophilic sols and lyophobic sols.
In lyophilic sols, the dispersed phase particles have great affinity (or love) for the dispersion medium. These sols are reversible. Examples include gum, gelatin, starch, proteins and rubber etc.
In lyophobic sols, the dispersed phase particles have no affinity (or love) for the dispersion medium. These sols are irreversible. Examples include solutions of metals such as gold and silver, metal hydroxides and metal sulphides.
The hydrophobic sols are less stable and easily coagulated than hydrophilic sols because, the stability of hydrophobic sols is due to charge only and the stability of hydrophilic sols is due to charge and solvation/ hydration.