Addition of non-volatile solute to a solvent always inceases the colligative properties such as osmotic pressure, `DeltaP, DeltaT_(b)` and `DeltaT_(f)`. All these colligative properties are direactly propertional to molality if solutions are dilute. The increase in colligative properties on addition of non-volatile solute is due to incease in number of solute particles.
For different aqueous solutions of `0.1 N NaCl, 0.1 N` urea, `0.1 N Na_(2)SO_(4)` and `0.1 N Na_(3)PO_(4)` solution at `27^(@)C`, the correct statement are :
`1g` mixture of glucose and urea present in `250 mL` aqueous solution shows an osmotic pressure of `0.74` atm at `27^(@) C`. Assuming solution to be dilture, which are correct ?
(P) Percentage of urea in solute mixture is `17.6`
(Q) Relative lowering in vapour pressure of this solutions is `5.41 xx 10^(-4)`.
(R) The solution will boil at `100.015^(@)C`, if `K_(b)` of water is `0.5 K "molality"^(-1)`
(S) If glucose is replaced by same amount of sucrose, the solution will show higher osmotic pressure at `27^(@)C`
(T) If glucose is repalced by same amount of `NaCl`, the solution will show lower osmotic pressure at `27^(@)C`.

Options

A. 1,2,3
B. 1,2,3,5
C. 2,4,5
D. 1,4,5

Answer

A

Explanation

(1) `0.74=(0.0821)/(250xx10^(-3))xx300((x)/(60)+(1-x)/(180))`
`x=0.176`
`%` urea `=(0.176)/(1)xx100=17.6`
(2) `(dP)/(P)=X_("solute")=((0.176)/(60)+(0.824)/(180))/(0.176/(60)+(0.824)/(180)+(250)/(18))=5.4xx10^(-4)`
(3) `DeltaT_(b)=mK_(b)=((40.176)/(60)+(0.824)/(180))xx(1000)/(250)xx0.5=0.015`
`DeltaT_(b)=100.015`.