In order to coagulate a fixed amount of `As_(2)S_(3),` sol, how will NaCl,`MgCl_(2)and AcCl_(3)` vary in their activity?

Explanation

Arseneous sulphide `(As_(2)S_(3))` is a negatively charges collloidal sol. In order to cause its coagulation, cations are the active ions. According to Hardy-Schulze rule, greaer the magnitude the positive charge on a particular cation, more will be its coagulating power. Thus, the coagulating powers of the cations present in electrolytes are : `NA^(+) lt Mg^(2+) lt Al^(3+).` In other words, equimolar solutions of the electrolytes listed will very in their coagulating power as : `AlCl_(3)gtMgCl_(2)gtNaCl.`