Coagulation The process of aggregation of colloidal particles into an insoluble precipitate by the addition of suitable electrolyte. Diffusion The process of movement of molecules from a region of higher concentration to a region of lower concentration. Peptisation The process of converting a precipitate into colloidal sol by shaking it with dispersion medium in the presence of small amount of electrolyte. Electrolysis The process by which electric current is passed through a substance to effect a chemical change.