Which of the following will have the highest coagulating power for `As_(2)S_(3)` colloid ?

Options

A. `PO_(4)^(3-)`
B. `SO_(4)^(2-)`
C. `Al^(3+)`
D. `Na^(+)`

Answer

C

Explanation

According to Hardy Schulze rule,
(i) Greather the valency of the active ion or flocculating ion, greather will be its coagulating power.
(ii) The ion carrying the charge opposite to that of sol particles are effective in cousing coagulation of the sol. Thus , to coagulate negative of `As_(2)S_(3)`, the coagulating power of `Al^(3+)` is more than `Na^(+)`