Question

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.

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 .

Step-by-step explanation: