Which has the maximum coagulating pawer for ferric hydroxide colloid?

Options

A. `AlCl_(3)`
B. `K_(4)[Fe(CN)_(6)]`
C. `BeSO_(4)`
D. `MgO`

Answer

B

Explanation

Ferric hydroxide is a postitive sol, `[Fe(OH)_(3)]Fe^(3+)`. Hence, to coagulate it, an anion is needed .`K_(4)[Fe(CN)_(6)]` gives the tetravalent anion `[Fe(CN)_(6)]^(4-)` , hence it has the greatest coagulating power among these (Hardy-Schulze law).