Out of `MgCl_(2) and AICI_(3)`, which one is more effective in causing coagulation of negatively charged sol and why?

Explanation

According to Schulze-Hardy rule, `AlCl_(3)` is more effective than `MgCl_(2)` in coagulation a negatively charged sol. This is because the charge of an `Al^(3+)` ion is more than the charge of a `Mg^(2+)` ion.