A colloidal sol is formed by moving AgNO3 and KI in 2. 1 molar ratio This colloidal sol is to be coagulatedI. NaI            II. MgSO4            III. AlPO4Molar ratio of these required to coagulate 1 mole colloidal sol is

AgNO3+KI⟶AgI+KNO3 AgI+AgNO3excess⟶[AgI]Ag+Fixed layer(colloidal)⋮NO3−By  [AgI] Ag + can be coagulated by negatively charged sol I- from Na, SO42− from MgSO4 and PO43− (from AlPO4. Greater the charge on anion, greater the coagulating power. (Hardy-Schulze rule)[AgI]Ag++I−⟶AgI+AgI2[AgI]Ag++SO42−⟶2AgI+Ag2SO43[AgI]Ag++PO43−⟶3AgI+Ag3PO4Thus, I- required by 1 mole colloidal sol = 1 moleSO42− required by 1 mole colloidal sol =12 mole PO43− required by 1 mole colloidal sol=13 mole  Ratio =1:12:13=6:3:2