How do you calculate percentage ionisation?

A sample of 0.100M sulfuric acid has a pH of 1.70



a) Calculate the hydronium ion concentration, [H30+], in the 0.1M sulfuric acid



b) On the basis of your answer to a), calculate the percentage ionisation for the second ionisation reaction (assuming the first ionisation is complete) ????



Please help!How do you calculate percentage ionisation?
[H3O+] = 10^-1.70 = 0.0200 M



% ionization = 0.0200 x 100 / 0.100 =20 %

north carolina dmv