1) Titration. This is a common laboratory method used to determine the unknown concentration of a substance.
2) We use a solution with a known concentration. This solution can be an acid (or a base). We fill a burette with this solution.
3) In a flask, we have the solution with unknown concentration and a known volume. It can be a base (or an acid).
4) Let the solution out of the burette and into the flask. We have to do this until the indicator changes color. Read the volume in the burette.
5) Finally, we have to calculate the concentration of the solution.