EDTA is a chemical used to treat some forms of lead poisoning. It can be theoretically donate four protons to an aqueous solution. Exactly halfway between the second and the third equivalence point, a total of 34.00 mL of base has been added and the pH reading is10.58. Make a rough sketch of a titration curve of EDTA with NaOH. Find out the hydronim ion concentration [H3O]+ in the solution and the value of Ka3 at this point in the titration?