Alanine has $p K_{a 1} = 2.34$ and $p K_{a 2} = 9.69$ . In an aqueous solution at pH 12, which statements are correct?

AIts net charge is close to $- 1$ .
BIn an electric field it migrates toward the anode.
CIt exists mainly as $H X_{2} N - CH (CH X_{3}) - COO X^{-}$ .
DIt exists mainly as the neutral zwitterion.

Answer: A, B, C

pH 12 is well above pKa2 (9.69), so the ammonium group is deprotonated and the carboxylate remains ionised: the species is the anion H2N-CH(CH3)-COO- with charge -1. Anions move toward the anode. The zwitterion dominates only between about pH 2.3 and 9.7.

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Alanine has pKa1​=2.34 and pKa2​=9.69. In an aqueous solution at pH 12, which statements are correct?

Answer: A, B, C

More questions on Amino acids: zwitterions, isoelectric point

Alanine has $p K_{a 1} = 2.34$ and $p K_{a 2} = 9.69$ . In an aqueous solution at pH 12, which statements are correct?