Write the mathematical form for mole fraction.

Explanation

Mathematically,
If `n_(1)` is the number of moles of solvent, If `n_(2)` is the number of moles of solute
Then mole fraction of solvent `=X_(1) =n_(1)/(n_(1) + n_(2))`
Mole fraction of solute `=X_(2) = n_(2)/(n_(1) + n_(2))`
Ex: Let 0.8 moles of NaOH is 0.2 moles of the `H_(2)O` then,
number of moles of water `=0/2/[0.8 + 0.2] = 0.2 = X_(1)`,
number of moles of NaOH `=0.8/[0.2 + 0.8] = 0.8 = X_(2)`