A student titrates 25.0 mL of 0.100 M NH₃ (Kb = 1.8 × 10⁻⁵) with 0.100 M HCl at 25 °C. After exactly enough HCl has been added to reach the equivalence point, what is the pH of the solution? (Assume volumes are additive.)
a) 7.00
b) 11.0
c) 5.28
d) 5.13