The coagulating power of electrolytes having inos `Na^(o+),Al^(3+)` and `Ba^(2+)` for arsenic sulphide sol increases in the order

Options

A. `Al^(3+)ltBa^(2+)ltNa^(+)`
B. `Al^(3+)ltNa^(+)ltBa^(2+)`
C. `Ba^(2+)ltNa^(+)ltAl^(+)`
D. `Na^(+)ltBa^(2+)ltAl^(3+)`

Answer

D

Explanation

Arsenic sulphide `(As_(2)S_(3))` is an anionic sol (negatively charged sol). Thus, its coagulation will depend upon coagulating power of cation. According to Hardy-Schulze rule, higher the valency of the coagulating ion added, the greater is its power to cause precipitation.
`Na^(+)ltBa^(2+)ltAl^(3+)`