A titration curve tells a full story about a reaction if you know what to look for, but most students only learn to find the equivalence point and stop there, missing the parts of the graph that carry the most information.
Strong acid and strong base curves
A strong acid titrated with a strong base starts at a low pH, stays relatively flat for most of the titration, then jumps sharply through the equivalence point before leveling off at high pH. The equivalence point for a strong acid and strong base titration is always pH 7, since the resulting solution contains only a neutral salt.
Weak acid curves are different, and that difference is tested
A weak acid titrated with a strong base starts at a higher pH than a strong acid would, since a weak acid doesn't fully dissociate. It also has a relatively flat buffer region before the equivalence point, since a mix of the weak acid and its conjugate base resists pH change there. The equivalence point itself lands above pH 7, not at 7, because the conjugate base left in solution makes it slightly basic.
The half-equivalence point
This is the single most tested fact in the whole titration curve topic. At exactly half the volume needed to reach the equivalence point, the concentration of the remaining weak acid equals the concentration of its conjugate base. According to the Henderson-Hasselbalch equation, when those two concentrations are equal, pH equals pKa exactly. That makes the half-equivalence point the fastest way to find a weak acid's Ka directly from a graph.
Where students actually lose points here
Assuming every equivalence point is pH 7
That's only true for a strong acid and strong base titration. A weak acid titration lands above 7, and a weak base titration lands below 7, since the leftover conjugate reacts with water.
Confusing the equivalence point with the half-equivalence point
The equivalence point is where moles of acid equal moles of base added. The half-equivalence point, at half that volume, is the one that gives pKa. Mixing these up is extremely common.
Misreading the equivalence point off the graph
The equivalence point is the steepest part of the curve, the inflection point, not simply where the curve looks the highest or flattest.
One of the highest value graphs on the exam
A titration curve question rewards being able to read several different pieces of information off one graph, which is exactly the kind of skill that gets faster with real practice.
Common questions
What is the half-equivalence point on a titration curve?
The point at exactly half the volume needed to reach the equivalence point. At that point, the concentration of the weak acid equals the concentration of its conjugate base, which means pH equals pKa.
Is the equivalence point always at pH 7?
No. It's only pH 7 for a strong acid titrated with a strong base. A weak acid and strong base titration has an equivalence point above pH 7, and a weak base and strong acid titration has one below pH 7.
How do you find the equivalence point on a graph?
It's the steepest point on the curve, the inflection point where the graph rises or falls most sharply, not simply the highest or flattest looking region.