The ionization state of amino acids is altered by a change in pH. At low pH, near the p K a pKa for the carboxylic acid, the - COOH - COOH proton is lost from the fully protonated form. As the pH approaches physiological levels, the zwitterionic form predominates. At high pH, near the p K a pKa for the amino group, one of the - NH + 3 - NH3 + protons is lost to form the fully deprotonated species.

Question

Chemistry

Amiyah Pearson

19 October, 00:36

The ionization state of amino acids is altered by a change in pH. At low pH, near the p K a pKa for the carboxylic acid, the - COOH - COOH proton is lost from the fully protonated form. As the pH approaches physiological levels, the zwitterionic form predominates. At high pH, near the p K a pKa for the amino group, one of the - NH + 3 - NH3 + protons is lost to form the fully deprotonated species.

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Marquez · Answer 1

The pH at which amino acid would not have net charge is 6

From the graph, it is obvious that zwitterion form that carries no net charge of amino acid exist at pH 4 to 8.

The Pink line shows the ionisation of carboxylic acid and green line shows ionisation of ammonium ion.

pH at which none of the green and pink line exist is the pH where complete zwitterion form exist (having no net charge).

So, pH 6 is the correct answer.