what is Bredig's Arc method?

Electrical disintegration or Bredig’s Arc method for preparation of colloids..− It involves dispersion as well as condensation. Colloidal sols of metals such as gold, silver, platinum, etc. can be prepared by this method.

 Electro-disintegration (Bredig's method) is employed for obtaining colloidal solution of metals like Au, Ag, Pt. An electric arc is set up between two metallic electrodes, suspended in a trough of water. Intense heat of arc converts metal into vapours, which are condensed immediately in the cold water bath, resulting in formation of particles of colloidal size.

(c). Peptization is the process of passing of a precipitate into colloidal particles on adding suitable electrolyte.