5.7: Quantitative Analysis Using Titration
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- 37001
The Learning Objective of this Module is to use titration methods to analyze solutions quantitatively.
To determine the amounts or concentrations of substances present in a sample, chemists use a combination of chemical reactions and stoichiometric calculations in a methodology called quantitative analysis (A methodology that combines chemical reactions and stoichiometric calculations to determine the amounts or concentrations of substances present in a sample). Suppose, for example, we know the identity of a certain compound in a solution but not its concentration. If the compound reacts rapidly and completely with another reactant, we may be able to use the reaction to determine the concentration of the compound of interest. In a titrationAn experimental procedure in which a carefully measured volume of a solution of known concentration is added to a measured volume of a solution containing a compound whose concentration is to be determined., a carefully measured volume of a solution of known concentration, called the titrantThe solution of known concentration that is reacted with a compound in a solution of unknown concentration in a titration., is added to a measured volume of a solution containing a compound whose concentration is to be determined (the unknown). The reaction used in a titration can be an acid–base reaction, a precipitation reaction, or an oxidation–reduction reaction. In all cases, the reaction chosen for the analysis must be fast, complete, and specific; that is, only the compound of interest should react with the titrant. The equivalence point (The point in a titration where a stoichiometric amount (i.e., the amount required to react completely with the unknown) of the titrant has been added) is reached when a stoichiometric amount of the titrant has been added—the amount required to react completely with the unknown.