Amino acids are building blocks of proteins. These compounds contain at least one amino gr...

Amino acids are building blocks of proteins. These compounds contain at least one amino group (−NH2) and one carboxyl group (−COOH), Consider glycine (NH2CH2COOH). Depending on the pH of the solution, glycine can exist in one of three possible forms:

Fully protonated: +NH3−CH2−COOH

Dipolar ion: +NH−CH2−COO−

Fully ionized: NH2−CH2−COO−

Predict the predominant form of glycine at pH 1.0, 7.0, and 12.0. The pKa of the carboxyl group is 2.3 and that of the ammonium group  is 9.6.