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Lyophobic Sol Preparation

1. Condensation methods - These methods involve chemical reaction , exchange of solvent and excessive cooling. Br2 + H2S ---> 2Hbr + S

2. Disintegration or dispersion technique

• Bredigs Arc Method - Electric arc is struck between two electrodes of metal whose sol is to be prepared after immersing in preferable ice cooled medium.

• Peptisation - Freshly prepared precipitate is added in small quantities  with constant stirring into a related electrolyte.
  

• Mechanical Disintegration - Suspension of dispersed phase in suitable dispersed medium is passed through two concentric steel discs to which rotate , this prepares a colloid solution.