Propanoic acid is partly dissociates in water. If the concentration of the acid is 0.0025 M in the solution and [H+] is determined to be 1.5 *10^-6 M. What is the acid dissociation constant for the propanoic acid?
I just don't believe these numbers and I have struggled with them for hours. If I look up Ka for propanoic acid and calculate the (H^+) for a beginning concn of 0.0025 M for Propanoic acid, I don't get anywhere near, not even close, to 1.5E-6 M. Please look at your question and check for typos. First, note that 0.0025 M is an extremely low concn. Trying to use that as a starting point to experimentally determine Ka for anything is risky. Also note that 1.5E-6 for (H^+) is getting so close to the H^+ furnished by water that some kind of correction would be required. The value I found for a 0.0025 M concentration for propanoic acid was 0.000177 M for the (H^+). I can resubstitute that number back into Ka and calculate it using the quadratic formula and it comes out OK. All of that leads me to believe that something about the post isn't right.
