Shown below is a potentiometric titration curve for a 0.050-g sample of an amino acid dissolved in water and titrated with 0.100 M NaOH. Based on this titration curve, answer the following questions:
(a) How many titratable acid/base sites does the amino acid have?
(b) Estimate the pKa for each of the acid-base sites you identified.
(c) Estimate the gram equivalent weight of the amino acid?