Electrogravimetry and Coulometry. Potentiometric measurements are made in the absence of current flow. The measured potential is that of a galvanic or voltaic . 22A The effect of current on cell potential When there is a net current in an electrochemical cell, the measured potential across the two electrodes is no longer. PDF | On Mar 3, , Subhrangsu Dey and others published Electrogravimetry and Coulometry.
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We think you have liked this presentation. If you wish to download it, please recommend it to your friends in any social system. Share buttons are a little bit lower. Published by Nelson Washington Modified over 2 years ago. Electrogravimetry and Coulometry Chapter 22 Bulk Electrolysis: Two additional phenomena, IR drop and polarization, must be considered. The following electrolytic cell for the determination of Cadmium II in HCl solutions can be considered: Ag AgCl sCl- 0.
The product of the resistance R of a cell in ohms V and the current I in amperes A is called the ohmic potential or the IR drop of the cell. In order to generate a current of I amperes in this cell, a potential that is IR volts more negative than the thermodynamic cell potential must be applied. Concentration polarization occurs because of the finite rate of mass transfer from the solution to the electrode surface.
It occurs when reactant species do not arrive at the surface of electroravimetry electrode or product species do not leave the surface of the electrode fast enough to maintain the desired current. Reactants are transported to the surface of an electrode by three mechanisms: Products are removed from electrode surfaces elctrogravimetry the same ways.
In the limiting current region, the electrode is said to be completely polarized since its potential can be changed widely without affecting the current. The current a and IR drop b decrease steadily with time. The cathode is maintained at V versus SCE throughout the experiment. The proportionality constant between the quantity measured and the analyte mass is calculated from accurately known physical constants. Electrical charge is the basis of the other electrical quantities, current, voltage, and power.
The charge required to convert the analyte to its reaction product is then determined by recording and integrating the current-versus-time curve during the electrolysis. The instrumentation for potentiostatic coulometry consists of an electrolysis cell, a potentiostat, and a device for determining the charge consumed by the analyte.
Electrogravimetry – Wikipedia
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Auth with social network: Registration Forgot your password? Electrogravimetry and Coulometry”— Presentation transcript: Download ppt “Bulk Electrolysis: OK Other Electrochemical Methods. About project SlidePlayer Terms of Service.