Titration Curves
Add a base drop by drop to an acid and follow the pH: almost flat at first, then a sudden jump at the equivalence point. Find the pH after any volume of titrant, and see the whole curve.
What Happens During a Titration?
In a titration you add a solution of known concentration from a burette until it has exactly reacted with the substance in the flask. Every drop of base neutralises some acid, but as long as acid is left over, the pH barely moves: the pH scale is logarithmic, so even halving the acid raises the pH by only 0.3.
At the equivalence point the last acid is gone. For a strong acid and a strong base the solution is then neutral, pH 7, and a single extra drop makes it strongly basic: the curve jumps steeply. An indicator that changes colour inside that steep part marks the end point.
Titration Curve
pHpH Along the Curve
your inputs| Volume added | Share of equivalence | pH |
|---|
Worked Techniques
The acid that is left over, divided by the total volume of the mixture.
The volume of titrant that contains exactly as many moles as the analyte.
Now the excess base sets the pH.
Sources & Verification
- S. S. Zumdahl & S. A. Zumdahl, Chemistry, 10th ed., Cengage, 2018 — Ch. 14 (Acids and Bases) and Ch. 15 (Acid–Base Equilibria).