An aqueous solution of 2% nonvolatile solute exerts a pressure of `1.004` bar at the boiling point of the solvent. What is the molar mass of the solute when `P_(A)^(@)` is `1.013` bar?

Explanation

`(triangle P)/(P_(A)^(@))= (W_(B)xx M_(A))/(M_(B)xx W_(A))`
In a 2% solution weight of the solute is 2g and solvent is 98g
`triangle P= P_(A)^(@)- P_("solution")= 1.013-1.004` bar `=0.009` bar
`M_(B)= (P_(A)^(@)xx W_(B)xx M_(A))/(triangle P xx W_(A))`
`M_(B)= 2xx 18xx 1.013"/"(98xx 0.009)`
`= 41.3g mol^(-1)`.