Titring

Titring, often spelled titration, is a laboratory technique used to determine the concentration of an unknown solution by adding a solution of known concentration, called the titrant, until the chemical reaction between the two solutions reaches a defined endpoint. In practice, the endpoint is identified by a color change of an indicator or by measuring a physical property such as pH or electrical potential. The method relies on stoichiometry: when the reaction is complete, the amount of titrant added corresponds to a known amount of analyte, allowing calculation of the analyte's concentration.

In a typical direct titration, a measured volume of the analyte is placed in a flask, and the titrant is slowly added from a burette with constant mixing. The process is stopped at the endpoint, and the concentrations are calculated using the formula C_titrant × V_titrant = C_analyte × V_analyte, adjusted for the reaction's stoichiometry. In back titration and other variants, the approach is tailored for sluggish reactions or poorly defined endpoints.

Common types include acid-base titrations with pH indicators or pH meters, redox titrations, complexometric titrations, and precipitation titrations. Indicators are chosen to provide a clear endpoint close to the equivalence point.

Equipment includes a burette, a pipette, a conical flask, and a suitable indicator or instrument. Applications span chemistry, biology, environmental testing, pharmaceuticals, and food analysis. Accuracy depends on standardizing the titrant, proper calibration, and careful technique. Titration methods have been refined since the 19th century and remain a fundamental analytical tool.