Question

On which of the following properties does the coagulating power of an ion depend?

• A. Both magnitude and sign of the charge on the ion
• B. The magnitude of the charge on the ion alone
• C. The sign of charge on the ion alone
• D. Size of the ion alone

Answer 1

The correct option is A Both magnitude and sign of the charge on the ion

The coagulating power of an ion depends on both magnitude and sign of the charge on the ion. The ions of the opposite sign of the charge to those present on the surface of the particles cause the precipitation of the particles. Thus, positively charged ions of the electrolyte will coagulate negatively charged particles. Similarly, negatively charged ions of the electrolyte will coagulate positively charged particles.

The coagulating power of an electrolyte increases very rapidly with an increase in the valence of anion or cation. Thus precipitating power of ions decrease in the order $A{l}^{3+}>M{g}^{2+}>N{a}^{+}$ and $P{O}_4^{3-}>S{O}_4^{2-}>C{l}^{-}$