Question

Which is the least effective substance for the co-agulation of $Fe(OH{)}_3$ colloid?

• A. $K_{2}S{O}_4$
• B. $K_{3}P{O}_4$
• C. $KBr$
• D. $K_4\left[Fe\right(CN{)}_6]$

Answer 1

The correct option is C $KBr$

KBr is least effective for coagulation of ferric hydroxide Sol. In KBr both cation and anion have least charge among given electrolytes. Higher is a charge on the ion, higher is its effectiveness for coagulation.