well i know sulfuric acid is stronger than other acids (like HF or HCl) because:

A. H2SO4 has TWO H+ ions instead of one, and

B. it just so happens that the ions dissociate in solution much more than other acids (some might only ionize 30% or whatever)

im only in a freshman chem class so i cant really tell you any more than that. i cant recall why it burns your skin.