Question

Arrange Fe³⁺, Na⁺, Ba²⁺, Sn⁴⁺ ions in the increasing order of their coagulating power to coagulate a negative sol.

Answer 1

Na⁺ < Ba²⁺ < Fe³⁺ < Sn⁴⁺

According to the Hardy–Schulze rule, the higher the valency of the oppositely charged ion, the greater its coagulating power. Here, Sn⁴⁺ has the highest valency, so the strongest effect.