Compute the ph after the addition of titrant

Question

A 100 mL volume of a 0.100 M weak base (pK_b = 5.00) was titrated with 1.00 M HClO₄. Find the pH at the following volumes of added acid:  0.00, 1.00, 5.00, 10.00, and 10.10 mL.

A 100.00 mL volume of 0.0400 M propionic acid (CH₃CH₂COOH; K_a = 1.34 ´ 10^-5) was titrated with 0.0837 M NaOH. Calculate the pH after the addition of: 0 V_e, 0.25 V_e, V_e, and 1.1 V_e mL of titrant where V_e is the volume of NaOH required to reach the equivalence point.