Difference between reference electrode and indicator electrode which originally containe mno4 and trated with fe
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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 electrodesare 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.
The overall electric potential is calculated as Ecell = Eind - Eref + Esol. 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. For example, the electrode reaction may be
Mn++ne−----->M
As the concentration of Mn+ changes,the Ecellchanges correspondingly. Thus the potentiometric titration involve measurement of Ecell with the addition of titrant. Types of potentiometric titration:
The overall electric potential is calculated as Ecell = Eind - Eref + Esol. 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. For example, the electrode reaction may be
Mn++ne−----->M
As the concentration of Mn+ changes,the Ecellchanges correspondingly. Thus the potentiometric titration involve measurement of Ecell with the addition of titrant. Types of potentiometric titration:
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Hey dear,
For potential measuremnt at least 2 electrodes are required -
1) Referrence electrode
2) Indicator electrode
● Referrence electrode -
- Referrence electrode is an electrode having an accurately maintained potential, used as a reference for measurement by other electrodes.
- A referrence electrode is used as half cell in electrochemical cell so that potential of the other half cell (indicator electrode) is determined.
Common referrence electrodes -
- Standard hydrogen electrode
- Saturated Calomel electrode
- Silver - silver chloride electrode
● Indiactor electrode -
- Indicator electrode is one at which potential is measured wrt referrence electrode.
- Any electrode (half cell) whose potential is to be measured can be used as indicator electrode.
Hope this helps you...
For potential measuremnt at least 2 electrodes are required -
1) Referrence electrode
2) Indicator electrode
● Referrence electrode -
- Referrence electrode is an electrode having an accurately maintained potential, used as a reference for measurement by other electrodes.
- A referrence electrode is used as half cell in electrochemical cell so that potential of the other half cell (indicator electrode) is determined.
Common referrence electrodes -
- Standard hydrogen electrode
- Saturated Calomel electrode
- Silver - silver chloride electrode
● Indiactor electrode -
- Indicator electrode is one at which potential is measured wrt referrence electrode.
- Any electrode (half cell) whose potential is to be measured can be used as indicator electrode.
Hope this helps you...
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