Sulfuric acid is diprotic and dissociates with two separate equilibria to yield two protons and a sulfate ion.
Accurately calculating the pH of a 0.1M H2SO4 solution requires making an approximation and performing a number of iterative calculations. This is true for every polyprotic substance. This process can be greatly simplified by constructing a graphing calculator program to perform the operations. (Approx-Cal.pdf)
