Question

A buffered solution is a solution that maintains a relatively constant pH despite of addition of strong acids or bases. Such a buffered solution often contains a mixture of weak acid (the protonated form of the acid, AH) and its conjugated base (the deprotonated form A^-). The buffer's pH is determined by the ratio of the deprotonated form to the protonated form (or A^- / HA) according to the Henderson–Hasselbalch equation.

Using the Henderson–Hasselbalch equation, calculate the pH of an carbonic acid/bicarbonate buffer solution made from 0.181 M H₂CO₃ and 0.01 M HCO₃^– . Carbonic acid's pK_a= 6.4.