Volumetric methods using oxidation and reduction reactions depend on the potential of half-reactions involved but, beyond favorable potential conditions, the oxidizing and reducing agents must be stable in solution and the substance to be determined should have a stable oxidation state, defined before the titration is started. Iodometry is an indirect volumetric method, where an excess of iodide ions are added to a solution containing the oxidizing agent, which react producing an equivalent quantity of iodine that is then titrated with a standardized solution of sodium thiosulfate.
half-reactions, oxidation state, volumetry, redox reactions, oxidizing agents, reducing agents, iodometry
João Carlos de Andrade
Universidade Estadual de Campinas, Instituto de Química
João C. de Andrade
Carol H. Collins
Attention: “Read carefully the procedure before starting the experiment. Do not perform the experiment without being monitored by your teacher. In doubt ask for help!”