The correct order is,II > III > IV > IIdentify the counter-ions in each electrolyteKCl:Cl−,K4[Fe(CN)6]:[Fe(CN)6]4−,K3PO4:PO43−,K2SO4:SO42−Charge −1,−4,−3,−2Now applying Hardy-Schulze ruleThe higher the charge of counter ions, the greater is precepitals powerFe(CN6)4−>PO43−>SO42−>Cl−