[SOS]

I understand that for strong acid/base titration, the pH is always going to be 7. But for weak acid/strong base titrations, and having the same amount of moles of weak acid/strong base..how do I calculate the pH at it's equivalent point?


What is the pH at the equivalence point in the titration of 100 mL of 0.25 M acetic acid
(Ka = 1.8 x 10 –5) with 0.25 M NaOH?

Answer: 8.92

[MrTeo]

Well, when your titration is over and you've reached the equivalence point you'll have a salt formed by a cation coming from a strong base (which obviously doesn't hydrolize) and an anion coming from a weak acid. So what you have to take into account is the hydrolysis of the last one and I hope you know how to calculate the pH of that.

[SOS]

Could you show me the steps?

0.1L x 0.25M =0.025 mol Acetic Acid
HA -> H+ + A-
0.1L x 0.25M =0.025 mol NaOH
NaOH -> Na+ + OH-

At the equivalence point, what's left over is A- and OH-..So..

That's the furthest I can get..

[Borek]

At the equivalence point, what's left over is A- and OH-..So..

No, at equivalence point you have just a salt. In your case - sodium acetate. So in fact the problem to solve is "What is pH of sodium acetate solution".