Question

Which of the following eletrolyte will have maximum flocculation value for $Fe{\left(OH\right)}_3$ sol?

• A. $NaCl$
• B. ${Na}_{2}S$
• C. ${\left({NH}_4\right)}_3{PO}_4$
• D. $K_2{SO}_4$

Answer 1

The correct option is A $NaCl$

Flocculating value $\propto \frac{1}{\left(z\right)}$ where $z=$ valency of coagulation ion.
Since, $Fe{\left(OH\right)}_3$ is a positively charged ions considering the valencies of various negative ions used i.e. ${Cl}^{-},S^{2-},{PO}_4^{3-}$ and ${SO}_4^{2-}$, we find the valency of ${Cl}^{-}$ is least so it will have maximum flocculation value i.e., $NaCl$