10mL of propanoic acid (Ka=5.5x10^-5) is titrated with 25mL of KOH (0.2M) to the equivalence point..

10mL of an unknown concentration of propanoic acid (Ka=5.5x10^-5) is titrated with 25mL of KOH (0.2M) to the equivalence point. What is the concentration of propanoic acid?

The Ka is not needed; the equivalence point occurs when the numbers of moles of acid equals the number of moles of base. Since propanoic acid is monoprotic, the equation is:

MaVa = MbVb
Ma = 0.2 M * 25 mL / 10 mL = 0.5 M

Ka would only be needed if you needed to know the pH at the equivalence point, which is not 7.

I mean equivalenve point

Report Abuse