Question

The coagulating power of electrolytes having $N{a}^{+}.A{l}^{3+}$ and $B{a}^{2+}$ for arsenic sulphide sol increases in the order

• A. $A{l}^{3+}<B{a}^{2+}<N{a}^{+}$
  
• B. $N{a}^{+}<B{a}^{2+}<A{l}^{3+}$
  
• C. $B{a}^{2+}<N{a}^{2+}<A{l}^{3+}$
  
• D. $A{l}^{3+}<N{a}^{+}<B{a}^{2+}$

Answer 1

The correct option is B $N{a}^{+}<B{a}^{2+}<A{l}^{3+}$

According to Hardy Schuize rule, greater the charge on oppositely charged ion, greater is its coagulating power. Since arsenic sulphide is a negatively charged sol, thus, the order of coagulating power is $Na+<B{a}^{2+}<A{l}^{3+}$