Question

1 mol of $\left[Ag\right]A{g}^{\oplus }$ sol is coagulated by :

• A. $1$ mol of $KI$
• B. $500$ mL of $1M$ $K_{2}S{O}_4$
• C. $300$ mL of $1M$ $N{a}_{3}P{O}_4$ solution
• D. $1$ mol of $AgI$

Answer 1

Answer: (A), (B)

The correct options are
A $1$ mol of $KI$
B $500$ mL of $1M$ $K_{2}S{O}_4$

The colloidal sols are stable due to the presence of electric charges on the colloidal particles. The particles do not come close to one another and coalesce because of the electric repulsion. The removal of charges by any means will lead to the aggregation of particles and hence, precipitation immediately. The process by means of which the particles of the dispersed phase in a sol are precipitated is known as coagulation or flocculation.

Here, $1$ mol of $\left[Ag\right]A{g}^{\oplus }$ sol has one mole of positive ions. So, it will be coagulated by one mole negative ions means $500$ mL of $1M$ $K_{2}S{O}_4$ and $1$ mol of $KI$.