Here is a good problem (hopefully):

What is the pH of a 1.0 (greek xi symbol) 10^-5 M solution of a tetraprotic acid with pK1 = 1.00, pK2 = 1.50, pK3 = 5.00, and pK4 = 10.00? Try to use early assumptions in the derivation of your equation to simplify the algebra, but remember to test every assumption you make.

This is a practice problem that my professor handed out. I really have no idea where to start...

so any help you can provide would be very nice..

also..what "assumptions" do u think my prof is referring to?

Thanks in advance--

Stephanie