Learn how and when to remove this template message Look up conductometry in Wiktionary, the free dictionary. Conductometry is a measurement of electrolytic conductivity to monitor a progress of chemical reaction. Conductometry has notable application in analytical chemistry , where conductometric titration is a standard technique. In usual analytical chemistry practice, the term conductometry is used as a synonym of conductometric titration, while the term conductimetry is used to describe non-titrative applications.
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Jump to navigation Jump to search Measurements, first and second derivative in a potentiometric titration. Potentiometric titration is a technique similar to direct titration of a redox reaction. It is a useful means of characterizing an acid. No indicator is used; instead the potential is measured across the analyte , typically an electrolyte solution. To do this, two electrodes are used, an indicator electrode the glass electrode and metal ion indicator electrode and a reference electrode.
Reference electrodes generally used are hydrogen electrodes, calomel electrodes, and silver chloride electrodes. The indicator electrode forms an electrochemical half cell with the interested ions in the test solution. The reference electrode forms the other half cell. Esol is the potential drop over the test solution between the two electrodes. Ecell is recorded at intervals as the titrant is added. A graph of potential against volume added can be drawn and the end point of the reaction is halfway between the jump in voltage.
Ecell depends on the concentration of the interested ions with which the indicator electrode is in contact. Thus the potentiometric titration involve measurement of Ecell with the addition of titrant. He titrated mercurous solution with potassium chloride, potassium bromide, and potassium iodide. If potassium chloride is added to mercurous nitrate on one side, mercury I chloride is precipitated. This decreased the osmotic pressure of mercury I ions on the side and creates a potential difference.
This potential difference increases slowly as additional potassium chloride is added, but then increases more rapidly. He found the greatest potential difference is achieved once all of the mercurous nitrate has been precipitated. This was used to discern end points of titrations. He introduced the idea of using potentiometric titrations for acids and bases that could not be titrated in conjunction with a colorimetric indicator  Potentiometric titrations were first used for redox titrations by Crotogino.
He titrated halide ions using potassium permanganate using a shiny platinum electrode and a calomel electrode. He says that if an oxidizing agent is added to a reducing solution then the equilibrium between the reducing substance and reaction product will shift towards the reaction product.
The changes the potential very slowly until the amount of reducing substance becomes very small. A large change in potential will occur then once a small addition of the titrating solution is added, as the final amounts of reducing agent are removed and the potential corresponds solely to the oxidizing agent. This large increase in potential difference signifies the endpoint of the reaction.
Elsevier, Thorburn, et al. Springer,
This contribution in case of a strong acid-strong base is negligible and is not considered there. As the titration progresses, the protons are neutralized to form water by the addition of NaOH. But if there is no chemical reaction in the electrolyte solutions, there will be an increase in the level of conductance. Retrieved 10 May Titrattion of Physical Chemistry. You will also require measuring circuits that will assist you in preventing concentration changes as a result of reactions at the electrodes.