Question

In an experiment, addition of $5.0$ mL of $0.006$ M $BaC{l}_2$ to $10.0$ mL of arsenic sulphite sol just causes the complete coagulation in $34$ hours. The flocculating value of the effective ion is_________.

• A. $2$
• B. $3$
• C. $4$
• D. $5$

Answer 1

The correct option is A $2$

In an experiment, addition of $5.0$ mL of $0.006$ M $BaC{l}_2$ to $10.0$ mL of arsenic sulphite sol just causes the complete coagulation in $34$ h.

The flocculating value of the effective ion is $2$.
$A{s}_2{S}_3$ sol is negatively charged owing to preferential adsorption of $S^{2-}$ ions.
Cation would be effective ion in coagulation.
Flocculating value $=$ Millimoles of the effective ion per litre of sol $=\frac{5\times 0.006\times {10}^3}{5+10}=2$