Question

Mole fraction of ethanol and water mixture is 0.25 . Hence percentage concentration of ethanol by weight of mixture is........

Answer 1

Given that the mole fraction of ethanol-water system is 0.25

i.e. solution contains 0.25 mol EtOH and 0.75 mol H2O

Mol wt of EtOH is 46.06 g/mol
Therefore 0.25 mol = 11.515 g of EtOH

Mol wt of H2O is 18.01528 g/mol
There fore 0.75 mol = 13.51 g of H2O

Total weight = 25.02646 gms

Wt % of EtOH is
11.515 / 25.02646 x 100
= 46.011 %