Question

The coagulating power of electrolytes having ions Na+, Al3+ and Ba2+ for arsenic sulphide sol increases in the order :

• A. $\mathrm { Al } ^ { 3 + } < \mathrm { Ba } ^ { 2 + } < \mathrm { Na } ^ { + }$
• B. $\mathrm { Na } ^ { + } < \mathrm { Ba } ^ { 2 + } < \mathrm { Al } ^ { 3 + }$
• C. $\mathrm { Ba } ^ { 2 + } < \mathrm { Na } ^ { + } < \mathrm { Al } ^ { 3 + }$
• D. $\mathrm { Al } ^ { 3 + } < \mathrm { Na } ^ { + } < \mathrm { Ba } ^ { 2 + }$

Answer 1

Answer: (B)

$\mathrm { Na } ^ { + } < \mathrm { Ba } ^ { 2 + } < \mathrm { Al } ^ { 3 + }$

Answer 2

According to Hardy Schulze rule, greater the charge on cation, greater is its coagulating power for negatively charged solution. So, order of coagulating power : Na+ < Ba2+ < Al3+.