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How do the chemical methods for preparation of colloids form a proper colloidal sol with a proper dispersed phase and dispersed medium? If so, then what is the dispersed phase and dispersed medium?

How do the chemical methods for preparation of colloids form a proper colloidal sol with a proper dispersed phase and dispersed medium? If so, then what is the dispersed phase and dispersed medium?

Grade:12

1 Answers

Sumit Majumdar IIT Delhi
askIITians Faculty 137 Points
8 years ago
Dear student,
We know that lyophilic sols may be prepared by simply warming the solid in a liquid dispersion medium. Whereas, lyophobic sols have to be prepared by special methods. These methods fall into two categories;
  • Condensation or Aggregation Methods.
  • Dispersion Methods.

Condensation or Aggregation Methods
These methods consist of chemical reactions wherein there is a change of solvent whereby the atoms or molecules of the dispersed phase appear first, then they aggregate to formcolloidal particles. The physical conditions should be such that they permitthe formation of sol particles but prevent the particles from becoming too large and thereby avoid formation of precipitate.

Dispersion Methods
In this method large particles of the substances are broken dpown into particles of colloidal dimensions in presence of dispersion medium. Since the sols formed are highly unstable. They are stabilized by adding some suitable stabilizer.

Thus to define, a colloid has a dispersed phase which consists of the suspended particles and a continuous phase which is the medium of suspension.
Regards
Sumit

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