Question

Calculate the mole fraction of benzene in solution containing 30% by mass inccl4

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 C6H6

= 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:

= no. of moles of C6H6 / (no. of moles of C6H6 + no. of moles of CCl4)


= 0.3846 / 0.3846 + 0.4545





= 0.458

Answer 2

Hey !!

Let the mass of solution be 100 g

Mass of Benzene = 30 g

Mass of carbon tetrachloride = 100 g - 30 g = 770 g

Number of moles of benzene = Mass / Molar mass

                     = 30 g / 78 g mol⁻¹

                     = 0.385 mol

Number of moles of carbon tetrachloride = Mass / Molar mass

                   = 70 g / 154 g mol⁻¹

                   = 0.455 mol

Mole fraction of benzene = Mass of benzene / Moles of benzene + Moles of tetrachloride

                 = 0.385 mol / 0.840 mol

FINAL RESULT  :- 0.458

Hope it helps you !!