JEE Main202126 Aug 2021Morning ShiftChemistrySolutionsActual
Of the following four aqueous solutions, the total number of those solutions whose freezing point is lower than that of 0 . 10 MC 2 H 5 OH is (Integer answer) (i) 0 . 10 M   Ba 3 PO 4 2 (ii) 0 . 10 M   Na 2 SO 4 (iii) 0 . 10 M   KCl (iv) 0 . 10 M   Li 3 PO 4
Correct answer
4
Step-by-step solution
ΔT f = ik f m As m is the same for all solutions so ΔT f depends on Van't Hoff factor (i). Greater is i small is freezing point.  Compound   i  C 2 H 5 OH 1 Ba 3 PO 4 2 5 Na 2 SO 4 3 KCl 2 Li 3 PO 4 4 So the given solutions have a lower freezing point than ethanol.