Question

The flocculation value of $HCl$ for $A{s}_2{S}_3$ sol is $30{\text{mmol L}}^{-1}$. If $H_{2}S{O}_4$ is used for the flocculation of arsenic sulphide, the amount, in grams, of $H_{2}S{O}_4$ in 250 mL required for the above purpose is .

Answer 1

For 1L sol 30 mmol of $HCl$ is required
For 1L sol 15 mmol of $H_{2}S{O}_4$ is required
For 250 mL of sol,
$\frac{15}{4}\times 98\times {10}^{-3}\text{g of}{H}_{2}S{O}_4=0.3675\text{g}$