How do pH and pKa relate?
Let's do an example:
What is the
Consider the equilibrium,
It is safe to assume that the hydroxide ion will consume one equivalent ammonium's protons, leaving
Since the total volume cancels out in the ratio of concentrations, we can translate these concentrations into mols and proceed.
To be sure, the hydroxide is treated as a strong base, and the ammonium as a weak acid.
: Nelson, D. L., Cox, M. M., & Lehninger, A. L. (2017). Lehninger Principles of Biochemistry. New York, NY: W.H. Freeman and Company.