Ferric chloride forms both positively and negatively charged sols. Explain.

Explanation

When `FeCl_(3)` is added to excess of hot water, a positively charged sol of hydrated ferric oxide is formed due to adsorption of ferric ions. `Fe_(2)O_(3).xH_(2)O //Fe^(3+)` is a positively charged sol.
When `FeCl_(3)` is added to alkali solution, a negatively charged sol of ferric oxide is formed due to adsorption of hydroxyl ions. `Fe_(2)O_(3).xH_(2)O //OH^(-)`  is a negatively charged sol.