Posted by Jonah on .
What is the pH of a solution that is .060M in potassium propionic and .085M in propionic acid?
Ka=1.3E-5 for the acid.
The answer is +4.73 but I don't know how to go about the problem. I thought that the potassium propionic was reacting with the acid to form their conjugate acid and base but I wa told that the acid would be reacting with water and dissociate forming the ions of the acid. I'm not sure how this works.
Use the Henderson-Hasselbalch equation. That's what you use for buffers.
pH = pKa + log (base)/(acid)
The base is the K salt and the acid is propionic acid.