Consider the titration of a 23.0-mL sample of 0.175 M CH3NH2(Kb=4.4104) with 0.145 M HBr.

Initial pH= 11.94

The volume of added acid required to reach the equivalence point= 27.8 mL

pH at 5.0 mL of added acid= 11.30

pH at the one-half equivalence point= 10.64

pH at equivalence point= 5.87

Determine the pH after adding 5.0 mL of acid beyond the equivalence point.