you're wrong.
H2SO4 + H2O -> H3O+ + HSO4-
HSO4- + H2O <-> H3O+ + SO4-
With the electronegativity crap, dude, the more electronegative the molecule is, the more "strong" the acid is. We dont go any further than "HCl, H2SO4, HNO3, etc etc are strong acids" but their strengths differ. more...