[ChristopherA]

The purpose is to characterise the solution, which is not entirely meaningless. Determining the specifics of chemical peeling reagents are important in my case, even if you feel otherwise. I simply asked if and how it is possible to determine.

[ChristopherA]

Thank you so much for your detailed explanation and I do apologise for the delay in replying. What I am trying to determine is if/how the pKa can be determine when combining these acids. The specific reason is in determining the specification of chemical peeling solutions. For example, combining 10% Lactic Acid (pKa 3.86) and 10% Trichloroacetic acid (pKa 0.7) in an aqueous chemical peeling solution that is a free acid, with no neutralisation and no pH adjustment. Is there a way to determine the resulting final pKa from combining these two acids? From reading your reply, is the pKa now somewhere between 3.86 and 0.7?

Sincere thanks for your consideration again. I hope the above provides more information.