Question

Equal volumes of each of two sols of AgI, one obtained by adding $AgN{O}_3$ to slight excess of KI and the other obtained by adding KI to slight excess of $AgN{O}_3$, are mixed together. Then:

• A. The two sols will stabilize each other
• B. The sol particle will acquire more electric charge
• C. The sols will coagulate each other mutually
• D. A true solution will be obtained

Answer 1

The correct option is C The sols will coagulate each other mutually

When $AgN{O}_3$ is added to excess KI then a negative sol is formed due to adsorption of $I^{-}$ ion from KI onto the AgI precipitate. Oppositely a poisitive sol is obtained when KI is added to $AgN{O}_3$ because $A{g}^{+}$ ions are adsorbed this time.
So the sols will coagulate each other mutually.