`x g` of non-electrolytic compound (molar mass =200) is dissolved in `1.0 L` of `0.05 M NaCl` solution. The osmotic pressure of this solution is found to be `4.92 atm` at `27^(@)C`. Calculate the value of `x`. Assume complete dissociation of `NaCl` and ideal behaviour of this solution.

Options

A. `17.959`
B. `18.959`
C. `19.959`
D. `16.959`

Answer

C

Explanation

For `NaCl : pi =iCRT=2xx0.05xx0.0821xx300`
`= 2.465`
For unknown compounds :
`pi = CRT = (x)/(100)xx 0.0821xx300=0.1231 x` atm
Total osmotic pressure `pi = pi_(1)+pi_(2)`
`4.92=2.463+0.123 x`
`x=19.959 g`