Question

For the coagulation of negative sol, the species below that has the highest flocculating power is:

Options

• \[\ce{SO^{2-}4}\]

• Ba⁺²

• Na⁺

• \[\ce{PO^{3-}4}\]

Answer 1

Ba⁺²

Explanation:

For the coagulation of a negative sol, the coagulating ion is a cation. According to the Hardy-Schulze rule, flocculating power increases with the valency of the ion. Among the given species, Ba⁺² (divalent cation) has higher flocculating power than Na⁺ (monovalent) and the anions \[\ce{SO^{2-}4}\] or \[\ce{PO^{3-}4}\], which are not effective for negative sol coagulation. Therefore, Ba⁺² has the highest flocculating power for coagulating a negative sol.