Flocculation value of $$BaCl_2$$ is much less than that of KCl for sol A and flocculation value of $$Na_2SO_4$$ is much less than that of NaBr for sol B. The correct statement among the following is :

The flocculation value is inversely proportional to the coagulating power of an active ion; a lower value means a higher valency ion is causing the coagulation.

For Sol A: $$\text{BaCl}_2$$ ($$\text{Ba}^{2+}$$) is more effective than $$\text{KCl}$$ ($$\text{K}^+$$). Since the higher-valency cation is causing coagulation, Sol A must be negatively charged.

For Sol B: $$\text{Na}_2\text{SO}_4$$ ($$\text{SO}_4^{2-}$$) is more effective than $$\text{NaBr}$$ ($$\text{Br}^-$$). Since the higher-valency anion is causing coagulation, Sol B must be positively charged.