Buffer (pH of a weak acid decreases when we add NaOH!! Yes, really.. This is not homework, but just something that I find not following general rule. Just wondering why. So We have the titration of 20.0 mL of .100M HF with .100M NaOH With 0mLof NaOH, the pH=2.08 (by calculating) But with 1.00mL of NaOH, the pH is 1.888 (by calculating) BUT then with 2.00ml of NaOH, the pH increases to 2.213 After that, it keeps increasing and follow the rule given the Ka= 6.8e-4 Can someone explain it?