Vapour pressure of a solution of `5g`of non-electrolyte in `100g`water at a particular temperature is`2985N//m^(2)`.The vapour pressure of pure water is`3000N//m^(2)`.The molecular weight of the solute is

Options

A. 60. 0
B. 120. 0
C. 180. 0
D. 380. 0

Answer

C

Explanation

`(DeltaP)/P^(@)=chi_(B)= rArr (DeltaP)/P^(@)=chi_(B)=(5//Mw_(B))/(5//Mw_(B) + 100//18)`
`rArr Mw_(B)=179.28 g "mol"^(-1)`