A 5. 25% solution of a non-electrolyte is isotonic with a 1. 5% solution of urea (molar mass = 60 g `mol^(-1)`) in the same solvent. If the densities of both the solution are assumed to be equal to 1 g `cm^(-3)` , than molar mass of nonelectrolyte substance will be:-

Options

A. 115 g `mol^(-1)`
B. 105 g `mol^(-1)`
C. 210 g `mol^(-1)`
D. 90 g `mo1^(-1)`

Answer

C

Explanation

Assume 100 ml solution in both cases, `therefore` for 5. 25% `W/v` &1. 5% `W/v` & `pi_1` = `pi_2`
`implies(5.25)/(M_W)=(1.5)/(60)`
`rArrM_W=(5.25xx60)/(1.5)=5.25xx40=210g`