Question

Which of the following will have maximum flocculation value for arsenic sulphide sol?

• A. $BaC{l}_2$
• B. $NaCl$
• C. $KCl$
• D. $AlC{l}_3$

Answer 1

Answer: (B)

$NaCl$

To coagulate negative sol of $A{s}_2{S}_3$, the coagulation power of different cations decrease in the order $A{l}^{3+}>B{a}^{2+}>K^{+}>N{a}^{+}$.

Hence, the flocculation value increases in the order $A{l}^{3+}<B{a}^{2+}<K^{+}<N{a}^{+}$

The flocculating values (in milli moles/litre) of $A{l}^{3+}<B{a}^{2+}<K^{+}<N{a}^{+}$ are 0.093, 0.69, 50 and 51 respectively.