In titrating 25 mL of a 0.2 M weak acid, HA, with 0.5 M of a strong base, say NaOH, the equivalence point is reached after 10 mL of base is added. I can calculate the pH by first setting up an ICE table to calculate the moles of A- remaining at the equivalence point, and then setting up an additional ICE table for the hydrolysis of A- to calculate the moles of OH- at the equivalence point. From that, I can determine the pOH and thus the pH.
My question is this: what would be the effect of adding more weak acid? Would I need to set up an ICE table with non-zero initial values for HA, OH-, and A-? If that's the case, then how do I determine the pH?