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

Explanation

`30%` of beneze 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 `= 100g - 30g = 70g`
Molar mass of benzene `(C_(6) H _(6)) = 78 mol^(-1)`
Molar mass of `C Cl_(4) = 12 +(4 xx 35.5) = 154 g mol^(-1)`
`therefore` No. of moles of benzene `= ("Mass")/("Molar mass") = (30g)/(78 mol ^(-1)) = 0.385`
No. of moles of `C Cl _(4) = ("Mass")/("Molar mass") = (70g)/(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 `C Cl_(4) =1- 0.458 =0.542`