The E-amino group of lysine has a pka of 10.5:
a) What fraction of these groups will be protonated in a dilute solution of lysine at pH 9.5?
b) At pH 11.0?
Please refer to the attached file. Cheers.
Here, the protonated form (acidic form) of lysine is symboled HA, and the de-protonated form (basic form) of lysine is symboled A-.
This solution contains step-by-step calculations to determine the protonation of lysine at pH 9.5 and 11. All formulas and workings are shown for better understanding.