Editing Electrolytic cell (section)

==Principles==
In an electrolytic cell, a [[Electric current|current]] passes through the cell by an external [[voltage]], causing a non-spontaneous chemical reaction to proceed. In a galvanic cell, the progress of a spontaneous chemical reaction causes an electric current to flow. An [[Chemical equilibrium|equilibrium]] electrochemical cell exists in the state between an electrolytic cell and a galvanic cell. The tendency of a spontaneous reaction to push a current through the external circuit is exactly balanced by a [[counter-electromotive force]] so that no current flows. If this counter-electromotive force is increased, the cell becomes an electrolytic cell, and if it is decreased, the cell becomes a galvanic cell.<ref>{{cite book |last=Mortimer |first=Robert G. |url=https://archive.org/details/physical-chemistry-3rd-edition-2008/ |title=Physical chemistry |publisher=Academic Press/Elsevier |year=2008 |isbn=978-0-12-370617-1 |edition=3rd |publication-place=Amsterdam |language=en |oclc=196313033 |via=Internet Archive}}</ref>{{Rp|page=354}}

An electrolytic cell has three components: an [[electrolyte]] and two electrodes (a [[cathode]] and an [[anode]]). The [[electrolyte]] is usually a [[Solution (chemistry)|solution]] of [[water]] or other [[solvent]]s in which [[ion]]s are dissolved. [[Molten salt]]s such as [[sodium chloride]] can also function as electrolytes. When driven by an external voltage applied to the electrodes, the ions in the electrolyte are attracted to an electrode with the opposite [[Electric charge|charge]], where charge-transferring (also called faradaic or [[redox]]) reactions can take place. Only with an external [[electrical potential]] (i.e., voltage) of correct polarity and sufficient magnitude can an electrolytic cell decompose a normally stable, or [[Chemically inert|inert]] chemical compound in the solution. The electrical energy provided can produce a chemical reaction that would otherwise not occur spontaneously.

[[Michael Faraday]] defined the cathode of a cell as the electrode to which cations (positively charged ions, such as silver ions Ag{{Su|p=+}}) flow within the cell, to be reduced by reacting with electrons (negatively charged) from that electrode. Likewise, he defined the anode as the electrode to which anions (negatively charged ions, like chloride ions Cl{{Su|p=−}}) flow within the cell, to be [[Redox|oxidized]] by depositing electrons on the electrode. To an external wire connected to the electrodes of a galvanic cell (or battery), forming an electric circuit, the cathode is positive and the anode is negative. Thus positive electric current flows from the cathode to the anode through the external circuit in the case of a galvanic cell.