In Al2(SO4)3, charge is higher, so the coagulating power is also higher. Sb2S3 sol is negatively charged sol. It will be coagulated by positively charged ions. In Al2(SO4)3,Al3+ ion has maximum charge among the given electrolytes. Among the electrolytes Na2SO4,CaCl2,Al2(SO4)3 and NH4Cl, the most effective coagulating agent for Sb2S3 sol is Al2(SO4)3.