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

Explanation

`30%` of benzene in carbon tetrachloride by mass means that
Mass of benzene in the solution = 30 g , `" "` Mass of solution = 100 g
`therefore" "` Mass of carbon tetrachloride `=100-30g=70g," "` Molar mass of benzene `(C_(6)H_(6))="78 g mol"^(-1)`
`"Molar mass of CCl"_(4)=12+4xx35.5="154 g mol"^(-1)`
`therefore" No. of moles of benzene"=("Mass")/("Molar mass")=("30 g")/("78 g mol"^(-1))=0.385`
`"No. of moles of CCl"_(4)=("Mass")/("Molar mass")=("70 g")/("154 g mol"^(-1))=0.455`
`"Mole fraction of benzene "=("Moles of benzene")/("Total moles in the solution")=(0.385)/(0.385+0.455)=(0.385)/(0.84)=0.458`
`"Mole fraction of CCl"_(4)=1-0.458=0.542`