Among the electrolysis of Na2SO4, CaCl2, Al2(SO4)3 and NH4Cl, the most effective coagulating agent for Sb2S3 sol is

Sb2S3 sol is a negative solA negative sol is coagulated by a cation,according to Hardy-schulze ruleCoagulating power of electrolyte ∞ valency of the ion possessing opposite charge to that solSb2S3 is most effectively coagulated by Al+3Coagulating power of Al+3> Ca+2>Na+ for a negative sol