Titration, also known as titrimetry or volumetric analyis, is a common laboratory method of quantitative chemical analysis that is used to determine the unknown concentration of a known reactant. A reagent, called the titrant or titrator, of a known concentration (a standard solution) and volume is used to react with a solution of the analyte or titrand, whose concentration is not known. The reaction is generally carried out in a glass flask containing the liquid or dissolved sample. Titrant solution is volumetrically delivered to the reaction flask using a calibrated burette. Delivery of the titrant is called a titration. The titration is complete when sufficient titrant has been added to react with all the analyte. This is called the equivalence point. An indicator is often added to the reaction flask to signal by colour change when all of the analyte has reacted. The titrant volume where the signal is generated is called the end point. The equivalence and end points are rarely the same. Endpoints can also be determined by other parameters like conductivity, pH, temperature, etc. In the classic strong acid-strong base titration for example, the endpoint of a titration is the point at which the pH of the reactant is just about equal to 7, and often when the solution takes on a persisting solid color as in the pink of phenolphthalein indicator.
Continue reading the full article