posted by Mark on .
If given the Ka or Kb and pKa and pKb, how do you find the initial concentration of a weak acid/base in a solution given the pH? Is there an equation for this? I can't find anything in my notes and am not sure what to look for.
HA ==> H^+ + A^-
Ka = (H^+)(A^-)/(HA)
Given the pH, convert to (H^+). That is the same as (A^-). You are given either Ka or pKa. That leaves only one unknown, (HA).