Question

A mixture of ethanol and water contains $54\%$ water by mass. Calculate the mole fraction of ethanol in this solution.

• A. 0.25
• B. 0.15
• C. 0.20
• D. 0.30

Answer 1

Answer: (A)

0.25

100g solution contains 54g water and 46 g ethanol

Moles of ethanol $=\frac{46}{46}=1$

Moles of water $=\frac{54}{18}=3$

Mole fraction of ethanol $=\frac{1}{1+3}=0.25$

Hence, the correct option is $A$