titrations

Titration is a quantitative chemical analysis technique used to determine the concentration of an unknown solution (the analyte) by reacting it with a solution of known concentration (the titrant). The process relies on a carefully measured addition of titrant until the reaction reaches a defined end point.

The typical apparatus includes a burette to deliver the titrant, a pipette to place a precise volume of the analyte in a flask, and an indicator or a pH meter to signal the end point. The analyst notes the initial volume in the burette, adds titrant gradually to the analyte while mixing, and records the final volume when the end point is reached. The end point is observed as a color change in an indicator or as a characteristic change in pH or potential. The end point should closely correspond to the equivalence point, where stoichiometrically equivalent amounts of reactants have reacted.

Calculation and interpretation follow from stoichiometry. At the equivalence point, the moles of titrant added equal the moles of analyte that reacted. For a simple acid–base titration, if the titrant is known and the analyte volume is known, the unknown concentration can be calculated from C_titrant × V_titrant = C_analyte × V_analyte.

Titrations are widely used for acid–base determinations, but variations exist, including redox titrations, complexometric titrations (such as with EDTA), and precipitation titrations. Standardization of the titrant and careful endpoint selection are important for accuracy.