Colloids are the dissolved state of substances that either do not pass, or pass very slowly through a parchment paper or animal membrane. If colloids have strong affinity between particles of dispersed phase and dispersion medium, they are called as lyophilic sols. Lyophilic sols are reversible in nature. They can be prepared again by simply mixing the dispersion medium with the dispersion phase and shaking the mixture. Lyophobic sols are those in which the dispersed phase has no attraction for the dispersion medium or the solvent. Their colloidal sols can be prepared only by special methods and they are irreversible in nature.
This video explains how to prepare lyophilic sols of (a) Starch, (b) Gum and (c) Egg albumin and lyophobic sols of (a) Ferric hydroxide, (b) Aluminium hydroxide and (c) Arsenious sulphide.