Redox Titrations

Key Concepts

A redox titration is a volumetric method that relies on the oxidation of the analyte (substance to be analysed).
The titrant (solution of known concentration) is often an oxidising agent.
At the equivalence point E_(forward) = E_(reverse), or, E_(cell) = 0
If the redox reaction does not produce a well-defined colour change at the equivalence point, an indicator should be used in the titration.
The redox titration curve is a plot of Electrode Potential (volts) vs volume of titrant or analyte.

Write a balanced half equation for the oxidation reaction.
Write a balanced half equation for the reduction reaction.
Add the oxidation and reduction half equations together to give a balanced redox reaction equation.
Extract all the relevant information from the question.
Check the data for consistency, for example, concentrations are often given in M or mol L^-1 but volumes are often given in mL. You will need to convert the mL to L for consistency. The easiest way to do this is to multiply the volume in mL x 10^-3.
Calculate the moles of reactant (titrant) (n) for which you have both volume (V) and concentration (M): n = M x V
From the redox reaction equation find the mole ratio of known reactant (titrant) : unkown reactant (analyte)
Calculate moles of unknown reactant (analyte) using this mole ratio.
From the volume (V) of the unknown reactant (analyte) and its calculated moles (n), calculate its concentration(M): M = n ÷ V