Question

A mixture of ethanol and water contains $54\%$ water by mass. Calculate the mole fraction of alcohol in this solution. If your answer is x, write the value of 100x.

Answer 1

Assume 100 g of the mixture are present.

Mass of water and methanol are 54 g and 46 g respectively.

The number of moles of water are $\frac{54}{18}=3$

The number of moles of ethanol are $\frac{46}{46}=1$

The mole fraction of ethanol is $\frac{1}{1+3}=0.25$

So, $100x=$ 25