As2 S3 sol is negatively charged owing to preferential adsorption of S2− ions.
Therefore, cation would be effective ion in coagulation.
Flocculating value = minimum milli moles of the effective ion per litre of sol
\(=\frac{4\times0.005\times10^3}{4+16}\)
= 1.0
The flocculating value of Ba2+ is 1.0
