So today I ran into an issue with an acid/base buffer problem I was given. The data points are as follows:
Compound X has a pKa of 3.1, and a second pKa between 3-5.
152 mL of 0.14M KOH was added to 29 mL of 0.22M of compound X. This resulted in a pH increase to 4.2 (final pH). What is the pKa of the second group (second pKa). The initial pH is 3.1.
I "Think" the answer is the second pKa being 3.75, but I don't know how to get there because of the excess strong base. Any help would be GREATLY appreciated.
(My work shows the confusion, I run out of HA- when I do my math, so how can i use HH to find pKa2?)