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

`(Delta P )/(P _(A) ^(0))= (W _(B) xx M _(A))/(M _(B) xx W_(A))`
In a `2%` solution weight of the solute is 2g and solvent is 98g
`Delta P = P _(A) ^(@) - P_("solution") =1. 013 -1.004` bar `=0.009 ` bar
`M _(B)= (P _(A) ^(0) xx W_(B) xx M _(A))/(Delta P xx W _(A))`
`M _(B) = (2 xx 18 xx 1. 013)/((98 xx 0.009)) =41.3 g mol^(-1)`