Colloids are classified on the basis of the

(ii) Nature of dispersed phase and dispersion medium:Colloids are classified into following.(1) AlcosolIt is a colloidal solution of a solid (dispersed phase) in alcohol (Dispersion medium).(2) AerosolIt is a colloidal solution of a liquid (dispersed phase) in gas (Dispersion medium). Example includes fog.(3) HydrosolIt is a colloidal solution of a solid (dispersed phase) in water (Dispersion medium).(4) 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.