Question

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

Answer 1

Let the total mass of the solution be 100 g and the mass of benzene be 30 g.

∴Mass of carbon tetrachloride = (100 − 30)g

= 70 g

Molar mass of benzene (C₆H₆) = (6 × 12 + 6 × 1) g mol⁻¹

= 78 g mol⁻¹

∴Number of moles of

= 0.3846 mol

Molar mass of carbon tetrachloride (CCl₄) = 1 × 12 + 4 × 355

= 154 g mol⁻¹

∴Number of moles of CCl₄

= 0.4545 mol

Thus, the mole fraction of C₆H₆ is given as:

= 0.458