We are asked to calculate the pH after 0.0 mL of HCl has been added.
Since no acid is added yet, we treat is as a simple weak base.
Step 1. Set up ICE chart:
Step 2. Calculate OH-
SInce Kb is small, assume x is negligible in the denominator.
x = [OH-] = 4.69 x 10-5 M
Consider the titration of 100.0 mL of 0.200 M HONH 2 by 0.100 M HCl. (K b for HONH2 = 1.1 x 10-8.)
a. Calculate the pH after 0.0 mL of HCl has been added.