At which of the following pH values does the amino acid have the best buffering capacity? The graph below is provided for ease of answering parts (d) and (e). It is a still image of the titration above. What is the pl (isoelectric point)? The graph below represents the titration of an amino acid with NaOH solution. View the titration and answer the questions below (parts a through e). At what pH is the average net charge - 1/2? Where does the amino acid have a net charge of-1? At what point has enough base been added to react with 1/2 of the NH3+ groups?