Titrauksen

Titraus (titration) is a quantitative chemical analysis method used to determine the concentration of an unknown solution by adding a titrant of known concentration from a calibrated burette until the reaction reaches its end point. In Finnish usage, "titrauksen" is the genitive form referring to the titration's end point or characteristics.

Principle: The volume of titrant required to reach the end point is related to the amount of analyte in the sample by stoichiometry. When the equivalence point is reached, stoichiometrically equivalent amounts have reacted, and the equation C_a V_a = C_t V_t applies.

End point determination: The end point is detected by an indicator that changes color, or by a potentiometric or pH measurement that signals the equivalence point. Common indicators include phenolphthalein for certain acid-base ranges and methyl orange for others, though choices depend on the expected pH at equivalence.

Titration types: Acid-base titration is the most common, but redox titration, complexometric titration (chelators such as EDTA), and precipitation titration are also used. Direct titration involves reacting analyte with titrant; back titration may be used when the reaction is slow or incomplete, or when the endpoint is easier to detect; indirect titration applies in specific cases.

Procedure and equipment: A clean burette is filled with the titrant; a pipette delivers a measured sample of the analyte to a flask; the indicator or sensor is added; titrant is added gradually while swirling until the end point is observed; volume is read from the burette and concentration calculated.

Applications and limitations: Titers are common in chemistry laboratories, pharmaceuticals, environmental testing, and food analysis. Accuracy depends on correct endpoint selection, standardization of the titrant, and careful technique; potential errors include misreading, air bubbles, and improper indicator choice.