What Is Titration? A Simple Guide to Measuring Concentration
By the BrainSnail editorial team. How these articles are written and checked, and how to tell us when one is wrong.
Titration is a laboratory method used to find the concentration of a solution by reacting it with another solution whose concentration is already known. The method depends on careful volume measurements, a balanced chemical equation, and a clear way to recognise when the required reaction has been reached.
A typical acid-base titration
In a typical acid base titration, one solution is measured into a flask and another is added slowly from a burette. The burette lets you measure how much solution has been delivered. If the concentration of the burette solution is known, the volume needed to react with the sample gives information about how many moles were present in the unknown solution.
The central idea in titration is stoichiometry. The balanced equation tells you the reacting ratio between the substances. For example, if one mole of an acid reacts with one mole of a base, reaching the correct reaction point means the moles added from the burette match the moles required by that ratio. Different reactions can have different mole ratios.
Titration can be used for more than acids and bases. Other versions rely on oxidation and reduction reactions, complex formation, or precipitation. The exact chemicals and endpoint method change, but the reasoning stays similar: add a measured amount of a known reagent until it has reacted in a predictable proportion with the substance being measured.
Indicators help you see an endpoint
Many titrations need a visible or measurable sign that enough reagent has been added. An acid base indicator changes colour over a particular pH range. You choose an indicator whose colour change occurs close to the equivalence point for the reaction being studied. Electronic pH meters can also track the change and help locate the endpoint more precisely.
When practising titration, it helps to separate two related terms. The equivalence point is the theoretical point where reactants have been mixed in the exact stoichiometric amounts required by the equation. The endpoint is the observed signal, such as a colour change. A well-chosen method makes those two points very close, but they are not identical definitions.
A careful titration follows a repeatable routine
A reliable titration is easier when every measurement is recorded clearly. A common school laboratory routine is:
- •Rinse and fill the burette with the solution of known concentration, then record the starting reading.
- •Measure a known volume of the unknown solution into a flask and add a suitable indicator if one is needed.
- •Add the burette solution while swirling, then slow to dropwise addition as the endpoint approaches.
- •Record the final burette reading and calculate the volume delivered.
- •Repeat until you have closely agreeing results rather than relying on one rushed trial.
After the experiment, the calculation usually follows a steady path. Use concentration and volume to find moles of the known solution, apply the mole ratio from the balanced equation, then use the sample volume to calculate the unknown concentration. When learning about titration, writing the units at every stage is one of the best error checks. Litres, moles, and moles per litre should connect cleanly.
The takeaway
Titration is a quantitative method that uses a known solution, a measured reaction volume, and stoichiometry to work out an unknown concentration. Focus on three pieces: accurate volume readings, the correct reaction ratio, and a dependable endpoint. Once those are clear, the calculation becomes a logical extension of the experiment rather than a formula to memorise.