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page 9 of 17 Question 5 We have 25.0 mL of a 0.400 M solution of HA(aq). We titrate this solution with a 0.400 M solution of NaOH(aq). The pH at the equivalence point is 9.66. (a) (2 points) Calculate the value of K for A-(aq), the conjugate base of HA (aq). (b) (3 points) Calculate the original pH of the 0.400 M solution of HA(aq). (c) (3 points) Caculate the pH after the addition of 15.0 mL of the NaOH(aq) solution to 25.0 mL of the 0.400 M solution of HA(aq). a) K = 1.0 10-8 b) 3.20 c) 6.18