Question

A solution containing 10 g per `dm^(3)` of urea (molecular mass = 60 g `mol^(–1)`) is isotonic with a 5% solution of a nonvolatile solute. The molecular mass of this nonvolatile solution is:
A. 250 g `mol^(–1)`
B. 300 g `mol^(–1)`
C. 350 g `mol^(–1)`
D. 200 g `mol^(–1)`

Answer 1

Correct Answer - B
For isotonic solution `pi_(1)=pi_(2)`
or `C_(1)=C_(2)`(conc.in mol/lit.)
(Urea solution)(unknown solution)
`(10)/(60)=(5xx1000)/(m_(w)xx100)`
`m_(w)=300 gm mol^(-1)`