Question

A solution contain 25%water,25%ethanol and 50%acetic acid by mass.calculate the mole fraction of each component.

Answer 1

For simplicity take: 25g H2O . 25g ethanol and 50g CH3COOH

Calculate mol of each:
molar mass H2O = 18g/mol
25g = 25/18 = 1.39 mol

Molar mass ethanol CH3CH2OH = 46g/mol
25g = 25/46 = 0.543 mol

Molar mass CH3COOH = 60g/mol
50g = 50/60 = 0.833 mol

Total mol = 1.39+0.543 +0.833 = 2.766 mol

Mol fraction H2O = 1.39/2.766 = 0.503
Mol fraction CH3CH2OH = 0.196
Mol fraction CH3COOH = 0.833/2.766 0.301