[twith89]

You have prepared a 0.2 M histidine solution. Calculate the molar concentration of isoelectric histidine at a) pH 5.5 b) pH 7.0. An "isoelectric amino acid" is the structure in which the molecule has no net charge.

Calculate the pH of a solution obtained by adding 20 ml of 0.20 M KOH to
480 ml of 0.02 M isoelectric glycine.

I am completely lost... I know you have to use the henderson hasselbach equation for the first question...

[Jorriss]

Do you know which equation tells you at which pH the isoelectronic point of an amino acid is?