Answer :
Final answer:
At a pH > 9, the ionized form of glycine will have a net negative charge due to the deprotonation of carboxyl and amine groups.
Explanation:
At a pH greater than 9, the ionized form of glycine will have a net negative charge. The isoelectric point (pI) of glycine is around 5.97, which is the pH at which glycine has an overall neutral charge due to the balance of positive and negative charges on the molecule. Above the pI, the carboxyl group (COOH) would exist mostly in its deprotonated form as COO-, and the amine group (NH2) would also be deprotonated to a lesser extent, forming NH-. Since the protonation state depends on the particular pH, at pH levels above the pI (particularly above pH 9 in this case), the amino acid will have one deprotonated amine group and one deprotonated carboxyl group, resulting in a net negative charge on the molecule.
