Final answer:
The pI of alanine if pKa values of 2.3 and 9.7 is 6.0 (Option C).
Step-by-step explanation:
The pI (isoelectric point) of a molecule is the pH at which it carries no net electrical charge. It can be calculated by averaging the pKa values of the ionizable groups in the molecule. In the case of alanine, it has one ionizable group which is the amino group (NH₃⁺).
The isoelectric point (pI) of an amino acid is the pH at which the amino acid has no net charge. To determine the pI of alanine, we take the average of the pKa values for the carboxyl group (pKa1) and the amino group (pKa2). Given alanine's pKa values of 2.3 (for the carboxyl group) and 9.7 (for the amino group), we use the formula:
pI = (pKa1 + pKa2) / 2
Thus, the pI of alanine is (2.3 + 9.7) / 2 = 6.0.
Therefore, the correct option is C.