The coagulating power of an electrolyte for arsenious sulphide decreases in the order

Hardy Schulze law can be defined as greater is the valency of the oppositely charged ion of the electrolyte is added, the faster is the coagulation. As2​S3​ is an anionic sol. Coagulating power of an electrolyte for arsenious sulphide depends on the coagulating power of cation which is directly proportional to the valency of the cation.The order is in the order: Al3+>Ba2+>Na+.