Question

Describe electrical dispersion method for preparation of sol.

Answer 1

Bredig's arc method is a method of preparation of colloidal solution, of metals such as gold, silver or platinum.

This method consists of both dispersion and condensation. An arc is struck between electrodes, under the surface of water containing some stabilizing agent such as traces of KOH (potassium hydroxide).The intense heat of the arc vaporizes some of the metal which then condenses under cold water. The water is kept cold as an ice bath.The Colloidal particle prepared is stabilised by adding a small amount of KOH to it.