Question

What is the mole fraction of benzene in solution containing $30\%$ by mass in carbon tetrachloride?

• A. 1.459
• B. 0.459
• C. 4.159
• D. None of these

Answer 1

Answer: (B)

0.459

Answer 2

$\because$ Mole fraction of a component $=\frac{\text { no. of moles of the component }}{\text { total no. of moles of all components }}$ Given, mass of benzene $=30 g$ So, moles of benzene $=\frac{30}{78}$ $\because$ Mol. mass of $C_{6} H_{6}=78$ $=0.385$ Mass of $C C l_{4}=70 g$ Moles of $C C l_{4}=\frac{70}{154}$ $\left(\because\right.$ Mol. mass of $\left.C C l_{4}=15.4\right)$ $=0.454$ $\therefore$ Mole fraction of benzene $\chi_{C_{6} H_{6}}=\frac{0.385}{0.385+0.454}$ $=0.459$