Mole Fraction

The of the moles of solute to the total number of moles fo both solvent and solute is the mole fraction of that solute.
in a solution containing nA moles of solute and nB moles of solvent, the mole fraction of solute, XA,
and mole fraction of the solvent Xa, can be expressed mathematically as,



Thus the mole fraction, X, is the ratio of the number of moles of one substance to the total number of moles of all the substances in the solution.
Note that mole fraction is a dimensionless quantity, that is, it has no unit. The sum of the mole fractions of all the components in a solution must equal to unity, that is 1.