Potentiometric titration
Encyclopedia
Potentiometric titration is a technique similar to direct titration
of a redox
reaction. No indicator
is used, instead the voltage
across the analyte
, typically an electrolyte solution is measured. To do this, two electrodes are used, a neutral electrode and a standard reference electrode
. The voltage is recorded at intervals as the titrant is added. A graph of voltage against volume added can be drawn and the end point of the reaction is half way between the jump in voltage.
EMF
of the cell depends on the concentration of the electrolytes with which the electrodes are in contact. Therefore, the electrode reaction is
Mn++ne------>M
As the concentration of Mn+ changes,the emf
of the cell also changes correspondingly
Thus the potentiometric titration involve measurement of emf between indicator electrode and reference electrode,with the addition of titrant.
types of potentiometric titration:
acid-base titration
(total alkalinity and total acidity), redox titration (HI/HY and cerate),
precipitation titration (halides), and complexometric titration (free EDTA and
Antical #5).
Titration
Titration, also known as titrimetry, is a common laboratory method of quantitative chemical analysis that is used to determine the unknown concentration of an identified analyte. Because volume measurements play a key role in titration, it is also known as volumetric analysis. A reagent, called the...
of a redox
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....
reaction. No indicator
Redox indicator
A redox indicator is an indicator that undergoes a definite color change at a specific electrode potential....
is used, instead the voltage
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
across the analyte
Analyte
An analyte, or component , is a substance or chemical constituent that is of interest in an analytical procedure. Grammatically, it is important to note that experiments always seek to measure properties of analytes—and that analytes themselves can never be measured. For instance, one cannot...
, typically an electrolyte solution is measured. To do this, two electrodes are used, a neutral electrode and a standard reference electrode
Reference electrode
A reference electrode is an electrode which has a stable and well-known electrode potential. The high stability of the electrode potential is usually reached by employing a redox system with constant concentrations of each participants of the redox reaction.There are many ways reference...
. The voltage is recorded at intervals as the titrant is added. A graph of voltage against volume added can be drawn and the end point of the reaction is half way between the jump in voltage.
EMF
EMF
- Music :* EMF , a British band** "EMF", a bonus track on EMF's album Schubert Dip* E.M.F. , a 1983 album by GG Allin* English Music Festival, a British music festival- Organizations :...
of the cell depends on the concentration of the electrolytes with which the electrodes are in contact. Therefore, the electrode reaction is
Mn++ne------>M
As the concentration of Mn+ changes,the emf
Electromotive force
In physics, electromotive force, emf , or electromotance refers to voltage generated by a battery or by the magnetic force according to Faraday's Law, which states that a time varying magnetic field will induce an electric current.It is important to note that the electromotive "force" is not a...
of the cell also changes correspondingly
Thus the potentiometric titration involve measurement of emf between indicator electrode and reference electrode,with the addition of titrant.
types of potentiometric titration:
acid-base titration
(total alkalinity and total acidity), redox titration (HI/HY and cerate),
precipitation titration (halides), and complexometric titration (free EDTA and
Antical #5).