The vapour pressure of pure liquid solvent 0.50 atm. When a non-volatile solute B is added to the solvent, its vapour pressure drops to 0.30 atm. Thus, mole fraction of the component B is

Options

A. `0.6`
B. `0.25`
C. `0.45`
D. `0.75`

Answer

A

Explanation

Binary mixture contain non-volatile solute (B) in volatile solvent. By Raoult's law, relative decrease in vapour pressure =
`(DeltaP)/(P^(@))=chi_(solute)=0.6`
`rArr(0.30)/(0.50)=chi_("solute")`
`:. chi_("solute")=0.6`