Which among the following will show maximum osmotic pressure?

(A) 1M Nacl

(B) 1M Mgcl₂

(C) 1M (NH₄)₃PO₄

(D) 1M Na₂SO₄

Please specify the reasons

Osmotic pressure is proportional to Vant Hoff factor , i at constant concentration.
Among the given ,
(NH4)3PO4 has the highest value of (i= 4).
For Nacl , i=2
Mgcl2, i=3
Na2SO4,i=3

So at 1M , ​(NH4)3PO4 will have the highest value of osmotic pressure .