Question

In a titration curve, how do i find the pH1/2??

Answer 1

I'm not sure what you mean. Do you mean pH of 1/2 or pH at the 1/2 way point.
pH = 0.5 gives (H^+) = 0.316 M.
pH at the 1/2 way point is pKa whatever that is (depends upon the acid).