What are the characteristics of the following colloids ? Give one example of each
(i) Multimolecular colloids
(ii) Lyophobic sol
(iii) Emulsions.

Explanation

(i) Multimolecular colloids: When large no. of small molecules or atoms (diameter `lt` 1mm) of a substance combine together in a disersion medium to form aggregate, which have size in the colloidal range, e.g. gold sol, sulphur sol etc.
(ii) Lyophobic sols: Substances which do not form colloidal sols on simply, mixing them with the dispersion medium are known as lyobtiobic colloids. They are unstable in nature and also known as irreversible sols. eg. metals, their sulphides etc.
(iii) Emulsions : Emulsions are liquid liquid colloidal systems eg. milk.