Ice

Figure . Bredig’s are method The ultrasonic vibrations produced by generator spread the oil and transfer the vibration to the vessel with mercury in water. (iv) Peptisation: By addition of suitable electrolytes, precipitated particles can be brought into colloidal state. The process is termed as peptisation and the electrolyte added is called peptising or dispersing agent.

AgCl AgCl Precipitate Colloid HCl  ) Condensation Methods: When the substance for colloidal particle is present as small sized particle, molecule or ion, they are brought to the colloidal dimension by condensation methods. Here care should be taken to produce the particle with colloidal size otherwise precipitation will occur. Various chemical methods for the formation of colloidal particles. (i) Oxidation: Sols of some non metals are prepared by this method.

(a) When hydroiodic acid is treated with iodic acid, I sol is obtained.