Determine the following characteristics of the titration curve for 25.0 mL of 0.400 M NH3(aq) titrated with 0.335 M HI(aq). (For NH3, Kb = 1.8x10-5.) (1a) The initial pH : (1b) The volume of HI(aq) required to reach the equivalence point : (1c) The pH at the half-neutralization point. (1d)The pH at the equivalence point