Peptising agent is added to convert precipitate into colloidal solution. Explain with an example.

Explanation

(i) Ions either positive or negative of peptizing agent (electrolyte) are adsorbed on the particles of precipitate. They repel and hit each other and break the particles of the precipitate into colloidal size.
(ii) For example, when we add a small volume of very dilute hydrochloric acid sotion peptising agent to a fresh precipitate of a silver chloride, it leads to formation of silver chloride colloidal solution, `underset("(Precipitate)")(AgCl)overset(HCl)rarrunderset("(Colloid)")(AgCl)`