At ph of 12 what charged groups would be present on glycine

Question

At ph of 12 what charged groups would be present on glycine

I said a NH2+ and coo- because a base accepts protons.

Thank you

I am not an organic chemist; however, I wonder, at a pH of 12, how there would be sufficient H^+ to form the NH2^+ ion? I can see the H^+ from the COOH group being removed at pH 12. Check my thinking.

Answer 1

You're correct in questioning the presence of NH2+ at a pH of 12. At pH 12, the solution is highly basic, which means there is an abundance of hydroxide ions (OH-) present. Under such conditions, the NH2 group of glycine would act as a base and accept a proton from the hydroxide ion, resulting in the formation of NH2-.

However, the COOH group of glycine is acidic and can lose a proton (H+) at higher pH values. At pH 12, the carboxyl group (COOH) of glycine is deprotonated and forms COO-.

Therefore, at a pH of 12, the charged groups present on glycine would be NH2- (created by accepting a proton from the hydroxide ion) and COO- (resulting from the deprotonation of the carboxyl group at higher pH values).