Colligative properties i.e., the properties of solution which depends upon the number pf aprticles present in solution are osmotic pressure, depression in freezing point, elevation in boiling point and lowering in vapour pressure. Experimental values of colligative properties for electroetically because electrolytes dissociates to furnish more ions in solution. On the other hand experimentally obtained values of colligative properties for associating nature of solute ate lower than those obtained theoretically. The ratio of experimantal colligative properties to theoretical colligative properties is called as van't Hoff factor `(i)`.
The correct order of osmotic pressure for the solutions :
(I) `1N` urea , (II) `1N NaCl`
(III) `1N Na_(2)SO_(4)` , (IV) `1N Na_(3)PO_(4)` is:

Options

A. `I gt II gt III gt IV`
B. `IV gt III gt II gt I`
C. `II gt III gt IV gt I`
D. `I gt IV gt III gt II`

Answer

C

Explanation

(i) Urea `= 1M = 1 xx 1 = 1`
(ii) `NaCl = 1M = 1 xx 2 = 2`
(iii) `Na_(2)SO_(4) = (1)/(2)M = (1)/(2) xx 3 = (3)/(2)`
(iv) `Na_(3)PO_(4) = (1)/(3) xx 4 = (4)/(3)`