<prompt> The buffering capacity of a buffer is maximum at pH equal to0.5 pKapKapKa12pKa  <response>: The pH of a buffer is determined by the Henderson-Hasselbalch equation So, at the max buffering capacity, . This is because a buffer reacts in the following manner--it is able to buffer against equal amounts of acid H or base OH- added. A- H - HA HA OH- - H2O A- Finally, we can see from the above Henderson-Hasselbalch equation that when , pH pKa. 