Calculate the mole fraction of benzene in a solution containing 30 % by mass of it in carbon tetrachloride.

Explanation

Let start with 100 g of the solution in which
Mass of benzene=30g
Mass of carbon tetrachloride=70g
Molar mass of benzene `(C_(6)H_(6))=6xx12+6xx1=78 g mol^(-1)`.
`n_(C_(6)_H_(6))=((30g))/((78g mol^(-1)))=0.385 mol`
Molar mass of carnon terachloride `(C CI_(4))=12+4xx35.5=154 "g mol"^(-1)`
`n_(C CI_(4))=((70g))/((154g mol^(-1)))=0.454 mol`
`x_(C_(6)H_(6))=(n_(C_(6)H_(6)))/(n_(C_(6)H_(6))+n_(C CI_(4)))=((0.385 mol))/((0.385 mol)+(0.454 mol))=0.459`