Electrolytes

An **electrolyte** is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an **ionic solution**, but molten electrolytes and solid electrolytes are also possible. Commonly, electrolytes are 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 charged functional groups. Electrolyte solutions are normally formed when a salt is placed 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 ions, according to the dissociation reaction NaCl(s) → Na+(aq) + Cl−(aq) It is also possible for substances to react with water 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. 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.



For example, your body fluids -- blood, plasma, interstitial fluid (fluid between cells) -- are like seawater and have a high concentration of **sodium chloride** (table salt, or NaCl). The electrolytes in sodium chloride are: As for your body, the major electrolytes are as follows: Electrolytes are important because they are what your cells (especially nerve, heart, muscle) use to maintain voltages across their cell membranes and to carry electrical impulses (nerve impulses, muscle contractions) across themselves and to other cells. Your kidneys work to keep the electrolyte concentrations in your blood constant despite changes in your body. For example, when you exercise heavily, you lose electrolytes in your sweat, particularly sodium and potassium. These electrolytes must be replaced to keep the electrolyte concentrations of your body fluids constant. So, many sports drinks have sodium chloride or potassium chloride added to them. They also have sugar and flavorings to provide your body with extra energy and to make the drink taste better. Many of these sports drinks have run their whole campaigns based on selling people electrolytes to replenish their bodies, often with sports celebrities as spokespeople.
 * ions that move to the cathode (**cations**) are positively charged
 * ions that move to the anode (**anions**) are negatively charged
 * **sodium ion** (Na+) - cation
 * **chloride ion** (Cl-) - anion
 * sodium (Na+)
 * potassium (K+)
 * chloride (Cl-)
 * calcium (Ca2+)
 * magnesium (Mg2+)
 * bicarbonate (HCO3-)
 * phosphate (PO42-)
 * sulfate (SO42-)