How is titration used in stoichiometric calculations?

Titration is used in stoichiometric calculations to determine the concentration of an unknown solution.

In a titration, a solution of known concentration (the titrant) is used to analyse an unknown solution (the analyte). The point at which the reaction between the two solutions is complete is known as the equivalence point. The volume of titrant needed to reach this point is used in stoichiometric calculations to determine the concentration of the analyte.

The process begins by adding a small amount of a strong acid or base to the analyte. This is done to establish a pH that is either very high or very low, which ensures that the reaction will go to completion. A pH indicator is also added to the analyte. This changes colour when the pH of the solution changes, indicating that the reaction is complete.

The titrant is then added to the analyte in small increments. The volume of titrant added is carefully measured. When the pH indicator changes colour, this indicates that the equivalence point has been reached. At this point, the moles of titrant can be calculated using the formula:

Moles of titrant = volume of titrant (in litres) x concentration of titrant (in mol/L)

The stoichiometry of the reaction is then used to calculate the moles of analyte. For example, if the reaction is 1:1, then the moles of analyte is equal to the moles of titrant. If the reaction is 2:1, then the moles of analyte is half the moles of titrant.

Finally, the concentration of the analyte can be calculated using the formula:

Concentration of analyte = moles of analyte / volume of analyte (in litres)

In this way, titration is used in stoichiometric calculations to determine the concentration of an unknown solution. This is a fundamental technique in analytical chemistry, and is widely used in both academic and industrial settings.