a)Chemical method: –
Colloidal solution can be prepared by chemical reaction leading to formation of molecules by double decomposition, oxidation, reduction or hydrolysis. These molecules then aggregate leading to form sols.
b)Electrical disintegration or Bredig’s Arc Method: –
Here Dispersion well working as a condensation. Gold and silver metals are produced from colloidal solution. In this method electric arc is act as struck between electrodes of metal immersed in the dispersion medium the intense heat product vaporized the metal, which then condenses to form particles of colloidal size.
Peptization is the “process of converting a precipitate into colloidal sol” by shaking it with dispersion medium in the presence of a small amount of electrolyte. Here the electrolyte is used as peptizing agent. During peptization the particulate absorbs the one of the ions of the electrolyte on its surface. This cause the development of +ve charge on precipitate, which ultimately break up into small particles of the size of a colloid.