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The terms anode and cathode are not defined by the voltage polarity of electrodes, but are usually defined by the direction of current through the electrode. An anode usually is the electrode of a device through which conventional current (positive charge) flows into the device from an external circuit, while a cathode usually is the electrode through which conventional current flows out of ...
An example is the electrolysis of an aqueous sodium chloride solution—although oxygen should be produced at the anode based on its potential, bubble overpotential causes chlorine to be produced instead, which allows the easy industrial production of chlorine and sodium hydroxide by electrolysis.
The cathode is in many ways the opposite of the anode. The name (also coined by Whewell) comes from the Greek words κάτω (kato), 'downwards' and ὁδός (hodós), 'a way'. It is the positive electrode, meaning the electrons flow from the electrical circuit through the cathode into the non-metallic part of the electrochemical cell.
When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. [2] The terminal marked negative is the source of electrons. When a battery is connected to an external electric load, those negatively charged electrons flow through the circuit and reach to the positive terminal, thus cause a redox ...
The cathode supplies electrons to the positively charged cations which flow to it from the electrolyte (even if the cell is galvanic, i.e., when the cathode is positive and therefore would be expected to repel the positively charged cations; this is due to electrode potential relative to the electrolyte solution being different for the anode ...
At the Zn anode, oxidation takes place (the metal loses electrons). This is represented in the following oxidation half reaction (note that the electrons are on the products side): + + At the Cu cathode, reduction takes place (electrons are accepted).
The one that is smaller will be the anode and will undergo oxidation. The cell potential is then calculated as the sum of the reduction potential for the cathode and the oxidation potential for the anode. E° cell = E° red (cathode) – E° red (anode) = E° red (cathode) + E° oxi (anode)
In electrochemistry, cell notation or cell representation is a shorthand method of expressing a reaction in an electrochemical cell.. In cell notation, the two half-cells are described by writing the formula of each individual chemical species involved in the redox reaction across the cell, with all other common ions and inert substances being ignored.