The concentration of electrolyte required to coagulate a given amount of As ₂ S ₃ sol is minimum in the case of

Step-by-step solution

The concentration of electrolyte required to coagulate a given amount of As ₂ ~S ₃ sol is minimum in case of aluminium nitrate. As ₂ ~S ₃ is negatively charge sol. In aluminium nitrate, the charge on Al cation is +3 which is maximum among given cations. Hence, its coagulating power is maximum.