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Electrolysis is a technique that uses a direct electric current (DC). Commercially, electrolytic cells are used in the electrorefining and electrowinning of several non-ferrous metals. Most high-purity aluminum , copper , zinc , and lead are produced industrially in electrolytic cells.
The exact relationship depends on the nature of the reactions at the two electrodes. For the electrolysis of aqueous copper(II) sulfate (CuSO 4) as an example, with Cu 2+ (aq) and SO 2− 4 (aq) ions, the cathode reaction is the reduction Cu 2+ (aq) + 2 e − → Cu(s) and the anode reaction is the corresponding oxidation of Cu to Cu 2+.
The protons flow from the anode to the cathode through the electrolyte after the reaction. At the same time, electrons are drawn from the anode to the cathode through an external circuit, producing direct current electricity. [citation needed] cathode At the cathode, another catalyst causes hydrogen ions, electrons, and oxygen to react, forming ...
The Downs cell uses a carbon anode and an iron cathode.The electrolyte is sodium chloride that has been heated to the liquid state. Although solid sodium chloride is a poor conductor of electricity, when molten the sodium and chloride ions are mobilized, which become charge carriers and allow conduction of electric current.
Pure water has a charge carrier density similar to semiconductors [12] [page needed] since it has a low autoionization, K w = 1.0×10 −14 at room temperature and thus pure water conducts current poorly, 0.055 μS/cm. [13] Unless a large potential is applied to increase the autoionization of water, electrolysis of pure water proceeds slowly ...
The net cell reaction yields hydrogen and oxygen gases. The reactions for one mole of water are shown below, with oxidation of oxide ions occurring at the anode and reduction of water occurring at the cathode. Anode: 2 O 2− → O 2 + 4 e −. Cathode: H 2 O + 2 e − → H 2 + O 2−. Net Reaction: 2 H 2 O → 2 H 2 + O 2
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 ...
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 ...