4.4 Classification of Colloids: Classification based on Physical State of Dispersed Phase and Dispersion Medium- Classification based on Nature of Interaction between Dispersed Phase and Dispersion Medium- Classification based on Type of Particles of the Dispersed Phase- Multimolecular, Macromolecular and Associated Colloids- Cleansing Action of Soaps- Preparation of Colloids- Purification of Colloidal Solutions- Properties of Colloidal Solutions: Tyndall effect, Colour, Brownian Movement- Charge on Colloidal Particles, Electrophoresis