Calculate Concentration of Four Forms of Histidine

Question

In a strong acid solution, the amino acid histidine binds three protons. The acid dissociation constants numbered from the weakest acid dissociation are 6.92 × 10^-10, 1.00 × 10^-6 and 1.51× 10^-2 at 298 K. Calculate the concentrations of the four forms of histidine (His-, HisH, HisH+ and HisH3 2+) in a 0.1 M solution of histidine at ph = 7, assuming that these constants apply at the ionic strength of the solution.

Summary

The question belongs to Chemical Engineering and it is about amino acid histidine binding three protons. The acid dissociation constants are given and four forms of histidine concentrations namely (His-, HisH, HisH+ and HisH3 2+) need to be calculated assuming ph = 7.

Note: The solution is in handwritten format