Calculate the mole fraction of H₂SO₄ in a solution containing 98% H₂SO₄ by mass.

$98\mathrm{\%}{\mathrm{H}}_2{\mathrm{SO}}_4\text{ means }98\text{ parts of }{\mathrm{H}}_2{\mathrm{SO}}_4$ is present in 100 parts of solution.
wt of H₂SO₄ = 98; molar mass of H₂SO₄ = 98
no.of moles of ${\mathrm{H}}_2{\mathrm{SO}}_4=\frac{98}{98}=1$
wt of H₂O = 100 – 98 = 2gm
m.w of H₂O =18
no.of moles of H₂O = $\frac{2}{18}=0.1$
Total moles in solution = 1 + 0.1 = 1.1
mole fraction of
${\mathrm{H}}_2{\mathrm{SO}}_4=\frac{\text{ No.of moles of }{\mathrm{H}}_2{\mathrm{SO}}_4}{\text{ Total moles of solution }}=\frac{1}{1.1}=0.9$