When organic compounds containing sulfur are burned, sulfur dioxide is produced. The amount of SO₂ formed can be determined by reaction with hydrogen peroxide:

H₂O₂(aq) + SO₂(g) → H₂SO₄(aq)

The resulting sulfuric acid is then titrated with a standard NaOH solution. A 1.325- g sample of coal is burned and the SO₂ collected in a solution of hydrogen peroxide. It took 28.44 mL of 0.1000 M NaOH to neutralize the resulting sulfuric acid. Calculate the mass percent of sulfur in the coal sample. Sulfuric acid has two acidic hydrogens.