Question

`As_2S_3` sol has a negative charge. Capacity to precipitate it is highest in
A. `AlCl_(3)`
B. `Na_(3)PO_(4)`
C. `CaCl_(2)`
D. `K_(2)SO_(4)`

Answer 1

Correct Answer - A
Negatively charged `As_(2)S_(3)` sol is coagulated most effectively by `AlCl_(3)`. This is because oppositely charged `Al^(+++)` ions have maximum charge.
`Al^(3+) gt Ca^(2+) gt Na^(+)`