![]() Concepts and Calculations in Analytical Chemistry, CRC Press: Boca Raton, 1992. Precipitation titrations often involve Ag + as either the analyte or titrant. Titrations with reducing agents also are possible. Because of their stability against air oxidation, most redox titrations use an oxidizing agent as a titrant. The most common titrant for a complexation titration is EDTA. Acid–base titrations use a strong acid or a strong base as a titrant. Titrimetric methods have been developed using acid–base, complexation, redox, and precipitation reactions. In a displacement titration the analyte displaces a reagent, usually from a complex, and the amount of displaced reagent is determined by an appropriate titration. When the reaction between the reagent and the analyte is complete, the amount of excess reagent is determined by a titration. In a back titration a reagent is added in excess to a solution containing the analyte. Other titration strategies may be used when a direct reaction between the analyte and titrant is not feasible. Many titrations are direct, in which the analyte participates in the titration as the titrand or the titrant. Knowing the shape of a titration curve is critical to evaluating the feasibility of a titrimetric method. In either case, an accurate result requires that the end point closely match the equivalence point. Alternatively, we can locate the end point by continuously monitoring a property of the titrand’s solution-absorbance, potential, and temperature are typical examples-that changes as the titration progresses. Experimentally we determine the titration’s end point using an indicator that changes color near the equivalence point. The volume of titrant corresponding to this stoichiometric reaction is called the equivalence point. In a titrimetric method of analysis, the volume of titrant reacting stoichiometrically with a titrand provides quantitative information about the amount of analyte in a sample.
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