Question

The electrolyte which has the least effect in the coagulation of $Fe{\left(OH\right)}_3$ sol is:

• A. potassium carbonate
• B. podium sulphate
• C. potassium ferrocyanide
• D. potassium iodide

Answer 1

The correct option is C potassium ferrocyanide

A sol is a colloid made out of very small solid particles in a continuous liquid medium. Sols are coagulated by oppositely charged ions. Greater the charge on ion causing coagulation, higher will be its coagulating power.

$K_3\left[Fe\right(CN{)}_6]\to 3K^{+}+[Fe(CN{)}_6{]}^{3-}$

Here potassium ferrocyanide smallest negative charge. So it has the least efect in the coagulation of $Fe(OH{)}_3$ sol.