Principles

Electrolytes commonly exist as solutions of acids, bases or salts. Furthermore, some gases may act as electrolytes under conditions of high temperature or low pressure. Electrolyte solutions can also result from the dissolution of some biological (e.g. DNA, polypeptides) and synthetic polymers (e.g. polystyrene sulfonate), termed polyelectrolytes, which contain multiple charged moieties. Electrolyte solutions are normally formed when a salt is placed (Bookmarks) into a solvent such as water and the individual components dissociate due to the thermodynamic interactions between solvent and solute molecules, in a process called solvation. For example, when table salt, NaCl, is placed in water, the salt (a solid) dissolves into its component elements, according to the dissociation reaction
NaCl(s) > Na+(aq) + Cl-(aq).

It is also possible for substances to react with water when they are added to it, producing ions, e.g. carbon dioxide gas dissolves in water to produce a solution which contains hydronium, carbonate, and hydrogen carbonate ions. Note that molten salts can be electrolytes as well. For instance, when sodium chloride is molten, the liquid conducts electricity.

Wetterstation

An electrolyte in a solution may be described as concentrated if it has a high concentration of ions, or dilute if it has a low concentration. If a high proportion of the solute dissociates to form free ions, the electrolyte is strong; if most of the solute does not dissociate, the electrolyte is weak. The properties of electrolytes may be exploited using electrolysis to extract constituent elements and compounds contained within the solution.