Which of the following solutions having same concentration will have lowest `pH` value?

Options

A. KCl
B. `MgCl_(2)`
C. `AlCl_(3)`
D. `Na_(3)PO_(4)`

Answer

C

Explanation

`As_(2)S_(3)` is a negatively charged sol. To cause its coagulation , the ions must be positively charged. Greater the magnitude of positive charged, greater will be its coagulating power. Thus `AlCl_(3)` containing `Al^(3+)` ion will be most effective in causing coagulation of `As_(2)S_(3)`.