Consider the titration of 40.00 mL of 0.10 M propanoic acid (K_a = 1.3 X 10^-5) that is titrated with 0.10 M NaOH. Represent propanoic acid as HA and its conjugate base as A^-.

Calculate the pH of the solution after the addition of 0.00 mL of 0.10 M NaOH (start of titration).

Calculate the pH of the solution after the addition of 20.00 mL of 0.10 M NaOH.

Calculate the pH of the solution after the addition of 30.00 mL of 0.10 M NaOH.

Calculate the pH of the solution after the addition of 40.00 mL of 0.10 M NaOH.