The solution of which one of the following will be least effective in coagulation of Fe(OH)_(3) sol ?

The solution of which one of the following will be least effective in

1.	The solution of which one of the following will be least effective in coagulation of Fe(OH)_(3) sol ?
Answer» `K_(4)[FE(CN)_(6)]` `K_(2)CrO_(4)` `KBr` `K_(2)SO_(4)` SOLUTION :`Fe(OH)_(3)` sol is positively charged. Ion with least NEGATIVE charge will be least effective.