Electrolyte

Source: Wikipedia, the free encyclopedia.
(Redirected from
Electrolytes
)
For the R.E.M. song, see Electrolite.

An electrolyte is a medium containing

anions, which disperse uniformly throughout the solvent.[4] Solid-state electrolytes also exist. In medicine and sometimes in chemistry, the term electrolyte refers to the substance that is dissolved.[5][6]

Electrically, such a solution is neutral. If an

synthetic polymers (e.g., polystyrene sulfonate), termed "polyelectrolytes", which contain charged functional groups. A substance that dissociates into ions in solution or in the melt acquires the capacity to conduct electricity. Sodium, potassium, chloride, calcium, magnesium, and phosphate
in a liquid phase are examples of electrolytes.

In medicine,

bulimia
.

In science, electrolytes are one of the main components of electrochemical cells.[2]

In clinical

metonymically to the ions, and (especially) to their concentrations
(in blood, serum, urine, or other fluids). Thus, mentions of electrolyte levels usually refer to the various ion concentrations, not to the fluid volumes.

Etymology

The word electrolyte derives from Ancient Greek ήλεκτρο- (ēlectro-), prefix related to electricity, and λυτός (lytos), meaning "able to be untied or loosened".[7]

History

Svante Arrhenius, father of the concept of electrolyte dissociation in aqueous solution for which he received the Nobel Prize in Chemistry in 1903

In his 1884 dissertation, Svante Arrhenius put forth his explanation of solid crystalline salts disassociating into paired charged particles when dissolved, for which he won the 1903 Nobel Prize in Chemistry.[8][9][10][11] Arrhenius's explanation was that in forming a solution, the salt dissociates into charged particles, to which Michael Faraday (1791-1867) had given the name "ions" many years earlier. Faraday's belief had been that ions were produced in the process of electrolysis. Arrhenius proposed that, even in the absence of an electric current, solutions of salts contained ions. He thus proposed that chemical reactions in solution were reactions between ions.[9][10][11]

Shortly after Arrhenius's hypothesis of ions, Franz Hofmeister and Siegmund Lewith[12][13][14] found that different ion types displayed different effects on such things as the solubility of proteins. A consistent ordering of these different ions on the magnitude of their effect arises consistently in many other systems as well. This has since become known as the Hofmeister series.

While the origins of these effects are not abundantly clear and have been debated throughout the past century, it has been suggested that the charge density of these ions is important[15] and might actually have explanations originating from the work of Charles-Augustin de Coulomb over 200 years ago.

Formation

Electrolyte solutions are normally formed when salt is placed into a

thermodynamic interactions between solvent and solute molecules, in a process called "solvation". For example, when table salt (sodium chloride), NaCl, is placed in water, the salt (a solid) dissolves into its component ions, according to the dissociation reaction[citation needed
]

NaCl(s) → Na+(aq) + Cl−(aq)

It is also possible for substances to react with water, producing ions. For example,

hydrogen carbonate ions.[citation needed
]

Molten salts can also be electrolytes as, for example, when sodium chloride is molten, the liquid conducts electricity. In particular, ionic liquids, which are molten salts with melting points below 100 °C,[16] are a type of highly conductive non-aqueous electrolytes and thus have found more and more applications in fuel cells and batteries.[17]

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.[citation needed]

Alkaline earth metals form hydroxides that are strong electrolytes with limited solubility in water, due to the strong attraction between their constituent ions. This limits their application to situations where high solubility is required.[18]

In 2021 researchers have found that electrolyte can "substantially facilitate electrochemical corrosion studies in less conductive media".[19]

Physiological importance

See also:
Water–electrolyte imbalance

In

hydrogen carbonate (HCO3−).[20][failed verification] The electric charge symbols of plus (+) and minus (−) indicate that the substance is ionic in nature and has an imbalanced distribution of electrons, the result of chemical dissociation. Sodium is the main electrolyte found in extracellular fluid and potassium is the main intracellular electrolyte;[21] both are involved in fluid balance and blood pressure control.[22]

All known multicellular lifeforms require a subtle and complex electrolyte balance between the

gradients of electrolytes is important. Such gradients affect and regulate the hydration of the body as well as blood pH, and are critical for nerve and muscle function. Various mechanisms exist in living species that keep the concentrations of different electrolytes under tight control.[23]

Both muscle tissue and

ion channels". For example, muscle contraction is dependent upon the presence of calcium (Ca2+), sodium (Na+), and potassium (K+). Without sufficient levels of these key electrolytes, muscle weakness or severe muscle contractions may occur.[citation needed
]

Electrolyte balance is maintained by oral, or in emergencies, intravenous (IV) intake of electrolyte-containing substances, and is regulated by

electrolyte disturbances, such as dehydration and overhydration, may lead to cardiac and neurological complications and, unless they are rapidly resolved, will result in a medical emergency
.

Measurement

Measurement of electrolytes is a commonly performed diagnostic procedure, performed via

specific gravity test to determine the occurrence of an electrolyte imbalance.[citation needed
]

Rehydration

In

diaphoresis (heavy sweating), diarrhea, vomiting, intoxication or starvation. Athletes exercising in extreme conditions (for three or more hours continuously, e.g. a marathon or triathlon) who do not consume electrolytes risk dehydration (or hyponatremia).[24]

A home-made electrolyte drink can be made by using water, sugar and salt in precise proportions.[25] It is important to include glucose (sugar) to utilise the co-transport mechanism of sodium and glucose. Commercial preparations are also available[26] for both human and veterinary use.

Electrolytes are commonly found in

fruit juices, sports drinks, milk, nuts, and many fruits and vegetables (whole or in juice form) (e.g., potatoes, avocados
).

Electrochemistry

Main article: Electrolysis

When electrodes are placed in an electrolyte and a voltage is applied, the electrolyte will conduct electricity. Lone electrons normally cannot pass through the electrolyte; instead, a chemical reaction occurs at the cathode, providing electrons to the electrolyte. Another reaction occurs at the anode, consuming electrons from the electrolyte. As a result, a negative charge cloud develops in the electrolyte around the cathode, and a positive charge develops around the anode. The ions in the electrolyte neutralize these charges, enabling the electrons to keep flowing and the reactions to continue.[citation needed]

Electrolytic cell producing chlorine (Cl2) and sodium hydroxide (NaOH) from a solution of common salt

For example, in a solution of ordinary table salt (sodium chloride, NaCl) in water, the cathode reaction will be

2 H2O + 2e− → 2 OH− + H2

and hydrogen gas will bubble up; the anode reaction is

2 NaCl → 2 Na+ + Cl2 + 2e−

and chlorine gas will be liberated into solution where it reacts with the sodium and hydroxyl ions to produce sodium hypochlorite - household bleach. The positively charged sodium ions Na+ will react toward the cathode, neutralizing the negative charge of OH− there, and the negatively charged hydroxide ions OH− will react toward the anode, neutralizing the positive charge of Na+ there. Without the ions from the electrolyte, the charges around the electrode would slow down continued electron flow; diffusion of H+ and OH− through water to the other electrode takes longer than movement of the much more prevalent salt ions. Electrolytes dissociate in water because water molecules are dipoles and the dipoles orient in an energetically favorable manner to solvate the ions.

In other systems, the electrode reactions can involve the metals of the electrodes as well as the ions of the electrolyte.

Electrolytic conductors are used in electronic devices where the chemical reaction at a metal-electrolyte interface yields useful effects.

  • In
    batteries, two materials with different electron affinities are used as electrodes; electrons flow from one electrode to the other outside of the battery, while inside the battery the circuit is closed by the electrolyte's ions. Here, the electrode reactions convert chemical energy to electrical energy.[27]
  • In some fuel cells, a solid electrolyte or proton conductor connects the plates electrically while keeping the hydrogen and oxygen fuel gases separated.[28]
  • In electroplating tanks, the electrolyte simultaneously deposits metal onto the object to be plated, and electrically connects that object in the circuit.
  • In operation-hours gauges, two thin columns of mercury are separated by a small electrolyte-filled gap, and, as charge is passed through the device, the metal dissolves on one side and plates out on the other, causing the visible gap to slowly move along.
  • In
    insulating
    coating, while the electrolyte layer behaves as one capacitor plate.
  • In some hygrometers the humidity of air is sensed by measuring the conductivity of a nearly dry electrolyte.
  • Hot, softened glass is an electrolytic conductor, and some glass manufacturers keep the glass molten by passing a large current through it.

Solid electrolytes

Main articles:
Fast ion conductor and Solid-state electrolyte

Solid electrolytes can be mostly divided into four groups described below.

Gel electrolytes

Gel electrolytes – closely resemble liquid electrolytes. In essence, they are liquids in a flexible

conductivity of such systems.[27][29]

Polymer electrolytes

Main article: Polymer electrolytes

Dry polymer electrolytes – differ from liquid and gel electrolytes in the sense that salt is dissolved directly into the solid medium. Usually it is a relatively high

mechanical strength and conductivity of such electrolytes, very often composites are used, and inert ceramic phase is introduced. There are two major classes of such electrolytes: polymer-in-ceramic, and ceramic-in-polymer.[30][31][32]

Ceramic electrolytes

Solid ceramic electrolytes –

lattice
. There are also glassy-ceramic electrolytes.

Organic plastic electrolytes

Organic ionic plastic crystals – are a type

protic organic salts formed by proton transfer from a Brønsted acid to a Brønsted base and in essence are protic ionic liquids in the molten state, have found to be promising solid-state proton conductors for fuel cells. Examples include 1,2,4-triazolium perfluorobutanesulfonate[28] and imidazolium methanesulfonate.[33]

See also

References

  1. S2CID 250852242. Archived
    from the original on 18 December 2021. Retrieved 18 December 2021.
  2. ^
    OCLC 1202758685
    .
  3. ISBN 978-3-527-34200-6
    .
  4. PMID 29611710
    .
  5. ISBN 978-1-58255-923-0
    .
  6. ^ "electrolyte". National Cancer Institute. 2 February 2011. Archived from the original on 23 April 2018. Retrieved 18 December 2021.
  7. ^ "Electrolyte - Definition, List of Electrolytes and Examples with Videos". BYJUS. Archived from the original on 3 February 2023. Retrieved 10 July 2022.
  8. ^ "The Nobel Prize in Chemistry 1903". Archived from the original on 8 July 2018. Retrieved 5 January 2017.
  9. ^
    ISBN 978-0-231035-729
    .
  10. ^
    ISBN 978-085-229553-3
    .
  11. ^
    ISBN 978-0-684101-125
    .
  12. ^ Franz Hofmeister (1888). "Zur Lehre Von Der Wirkung Der Salze". Naunyn-Schmiedeberg's Arch. Pharmacol.
  13. doi:10.1016/j.cocis.2004.05.005. Archived
    from the original on 20 January 2022. Retrieved 8 November 2021.
  14. PMID 35543205
    .
  15. S2CID 244578563
    .
  16. ISSN 0441-3776. Archived from the original
    (PDF) on 2 March 2017. Retrieved 1 March 2017.
  17. ^ Jiangshui Luo, Jin Hu, Wolfgang Saak, Rüdiger Beckhaus, Gunther Wittstock, Ivo F. J. Vankelecom, Carsten Agert, Olaf Conrad (2011). "Protic ionic liquid and ionic melts prepared from methanesulfonic acid and 1H-1,2,4-triazole as high temperature PEMFC electrolytes".
    S2CID 94400312
    .
  18. ^ Brown, Chemistry: The Central Science, 14th edition, pg. 680.
  19. S2CID 229508133
    .
  20. ^
    PMID 32272658
    .
  21. ^ Ye S(, Tang Z( (1986). 细胞膜钠泵及其临床意义. 上海医学 [Shanghai Medicine] (in Simplified Chinese) (1): 1. Archived from the original on 3 March 2017. Retrieved 3 March 2017.
  22. ^ Tu Z( (2004). 电解质紊乱对晚期肿瘤的治疗影响. 中华中西医杂志 [Chinese Magazine of Chinese and Western Medicine] (in Simplified Chinese) (10). 张定昌. 在正常人体内，钠离子占细胞外液阳离子总量的92%，钾离子占细胞内液阳离子总量的98%左右。钠、钾离子的相对平衡，维持着整个细胞的功能和结构的完整。钠、钾是人体内最主要的电解质成分...
  23. ^ Open Resources for Nursing, Ernstmeyer K, Christman E (2021), "Chapter 15 Fluids and Electrolytes", Nursing Fundamentals [Internet], Chippewa Valley Technical College, retrieved 28 February 2024
  24. PMID 18347684
    .
  25. ^ "Rehydration drinks". Webmd.com. 28 April 2008. Archived from the original on 23 October 2008. Retrieved 25 December 2018.
  26. ^ "Oral Rehydration Salt Suppliers". Rehydrate.org. 7 October 2014. Archived from the original on 7 December 2014. Retrieved 4 December 2014.
  27. ^
    doi:10.1016/j.electacta.2011.06.014
    .
  28. ^ a b c d Jiangshui Luo, Annemette H. Jensen, Neil R. Brooks, Jeroen Sniekers, Martin Knipper, David Aili, Qingfeng Li, Bram Vanroy, Michael Wübbenhorst, Feng Yan, Luc Van Meervelt, Zhigang Shao, Jianhua Fang, Zheng-Hong Luo, Dirk E. De Vos, Koen Binnemans, Jan Fransaer (2015). "1,2,4-Triazolium perfluorobutanesulfonate as an archetypal pure protic organic ionic plastic crystal electrolyte for all-solid-state fuel cells".
    S2CID 84176511
    .
  29. ^ "The Roll-to-Roll Battery Revolution". Ev World. Archived from the original on 10 July 2011. Retrieved 20 August 2010.
  30. ISSN 0378-7753
    .
  31. ISSN 0013-4686
    .
  32. ISSN 0378-7753
    .
  33. ^ Jiangshui Luo, Olaf Conrad, Ivo F. J. Vankelecom (2013). "Imidazolium methanesulfonate as a high temperature proton conductor".
    S2CID 96622511
    .

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Electrolyte&oldid=1218379574"