Question

The correct order of coagulating power of the given cations in the coagulation of a negative sol, is:

• A. $A{l}^{3+}>B{a}^{2+}>N{a}^{+}$
• B. $N{a}^{+}>B{a}^{2+}>A{l}^{3+}$
• C. $N{a}^{+}>A{l}^{3+}>B{a}^{2+}$
• D. $B{a}^{2+}>A{l}^{3+}>N{a}^{+}$

Answer 1

The correct option is A $A{l}^{3+}>B{a}^{2+}>N{a}^{+}$

Generally, greater the valence of the flocculating ion added, the greater is its power to cause precipitation. This is known as Hardy-Schulze rule. In the coagulation of a negative sol, the flocculating power is in the order: $A{l}^{3+}>B{a}^{2+}>N{a}^{+}$.