State “Hardy Schulze Rule” with one example.
The Hardy-Schulze rule asserts that the higher the valency of an electrolyte's oppositely charged ion, the faster it coagulates. The attraction is based on electrostatic forces. The coagulation power is proportional to the valency of the flocculation ion. For example, trivalent cations such as Al3+ are thought to be more successful at coagulating negatively charged arsenious sulphide sol.
