How do I find PKA on a titration curve?

As the acid or the base being titrated becomes weaker (its pKa or pKb becomes larger), the pH change around the equivalence point decreases significantly. With very dilute solutions, the curve becomes so shallow that it can no longer be used to determine the equivalence poin

How do I find PKA on a titration curve?

1. Find the endpoint.
2. Read the titrant volume at the endpoint.
3. Find exactly one-half the volume at the endpoint.
4. Read the pH at that half-equivalence-point volume.
5. Voilà, la pKa.