For 0.100 M of weak acid (propanoic acid HPr) the Ka is given by 1.30 x10-5 , calculate the pH of the sample.

Answer 1

HPr ==> H^+ + Pr^-
Set up an ICE chart.
Ka = (H^+)(Pr^-)/(HPr)
Solve for (H^+) and convert to pH.
Post your work if you get stuck.