Question

out of mgcl2 and alc3 which is effective in causing coagulation of negatively charged solution and why

Answer 1

According to Hardy Schulze rule : The coagulating power of an ion depend on both magnitude and sign of the charge of the ion .

i.e for -vely charged colloid we need +ve ions and vice versa

also greater the magnitude of charge on coagulating ion, greater is its coagulating power

and among the +ve ions, Al ³⁺ has greater magnitude of charge. so answer is AlCl₃