Liquid bleach, often called just bleach, is a common chemical household product that consists of a dilute

solution Solution may refer to: * Solution (chemistry), a mixture where one substance is dissolved in another * Solution (equation), in mathematics ** Numerical solution, in numerical analysis, approximate solutions within specified error bounds * Solu ...

sodium hypochlorite Sodium hypochlorite is an alkaline inorganic chemical compound with the formula (also written as NaClO). It is commonly known in a dilute aqueous solution as bleach or chlorine bleach. It is the sodium salt of hypochlorous acid, consisting of ...

() and other secondary ingredients. It is a chlorine releasing bleaching agent widely used to whiten clothes and remove stains, as a

disinfectant A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than ...

to kill

germ Germ or germs may refer to: Science * Germ (microorganism), an informal word for a pathogen * Germ cell, cell that gives rise to the gametes of an organism that reproduces sexually * Germ layer, a primary layer of cells that forms during embry ...

s, and for several other uses. While the term has had this meaning for a long time, it may now be applied more generically to any liquid

bleaching agent Bleach is the generic name for any chemical product that is used industrially or domestically to remove color from (i.e. to whiten) fabric or fiber (in a process called bleaching) or to disinfect after cleaning. It often refers specifically t ...

for laundry, irrespective of composition, such as

peroxide-based bleach A peroxide-based bleach or simply peroxide bleach is any bleach product that is based on the peroxide chemical group, namely two oxygen atoms connected by a single bond, (–O–O–). This bond is fairly weak and is often broken in chemical react ...

es.

History

Potassium hypochlorite () was synthesized by

French French may refer to: * Something of, from, or related to France ** French language, which originated in France ** French people, a nation and ethnic group ** French cuisine, cooking traditions and practices Arts and media * The French (band), ...

scientist

Berthollet Claude Louis Berthollet (, 9 December 1748 – 6 November 1822) was a Savoyard-French chemist who became vice president of the French Senate in 1804. He is known for his scientific contributions to the theory of chemical equilibria via the ...

in 1789, by reacting

chlorine Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...

gas () with a solution of

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

(potash, ). He also discovered its cloth bleaching properties, and set out to commercialize it under the name of ''Eau de Javel'' ("water of Javel") after the borough of

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...

where it was manufactured. It was the first product intended specifically for that application, and it shortened the process of bleaching newly made cloth from months to hours.

Scottish Scottish usually refers to something of, from, or related to Scotland, including: *Scottish Gaelic, a Celtic Goidelic language of the Indo-European language family native to Scotland *Scottish English *Scottish national identity, the Scottish ide ...

chemist and industrialist

Charles Tennant Charles Tennant (3 May 1768 – 1 October 1838) was a Scottish chemist and industrialist. He discovered Calcium hypochlorite, bleaching powder and founded an industrial dynasty. Biography Charles Tennant was born at Laigh Corton, Alloway, Ayrs ...

proposed in 1798 a solution of

calcium hypochlorite Calcium hypochlorite is an inorganic compound with chemical formula , also written as . It is a white solid, although commercial samples appear yellow. It strongly smells of chlorine, owing to its slow decomposition in moist air. This compound is ...

as an alternative for Javel water, and patented bleaching powder (solid

, Ca(ClO)₂) in 1799. Around 1820,

Antoine Labarraque Antoine Germain Labarraque (28 March 1777 – 9 December 1850)Maurice Bouvet. Les grands pharmaciens: Labarraque (1777-1850)' (Revue d'histoire de la pharmacie, 1950, Volume 38, no. 128, pp. 97-107). was a French chemist and pharmacist, notable f ...

substituted the much cheaper precursor

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

(soda lye, ) for potash, thus producing ''Eau de Labarraque'', basically the same "liquid bleach" (NaClO) still in use today. He also discovered its disinfectant properties, and was instrumental in spreading it worldwide for that purpose.Scott, James, transl. (1828).
On the disinfecting properties of Labarraque's preparations of chlorine
' Published by S. Highley. His work greatly improved medical practice, public health, the sanitary conditions in hospitals,

slaughterhouse In livestock agriculture and the meat industry, a slaughterhouse, also called an abattoir (), is a facility where livestock animals are slaughtered to provide food. Slaughterhouses supply meat, which then becomes the responsibility of a mea ...

s, and all industries dealing with animal products—decades before

Pasteur Louis Pasteur (, ; 27 December 1822 – 28 September 1895) was a French chemist, pharmacist, and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation, and pasteurization, the last of which wa ...

and others established the

germ theory of disease The germ theory of disease is the currently accepted scientific theory for many diseases. It states that microorganisms known as pathogens or "germs" can cause disease. These small organisms, which are too small to be seen without magnification, ...

.Labarraque, Antoine-Germain
''

Nouvelle biographie générale Nouvelle is a French word, the feminine form of "new". It may refer to: ;Places * Nouvelle, Quebec, a municipality in Quebec, Canada * Nouvelle-Église, a commune in the Pas-de-Calais department, France * Port-la-Nouvelle, a commune in the Aude dep ...

'', volume 28 (1859), columns 323-324. In particular, it led to the nearly universal practice of chlorination of tap water to prevent the spread of diseases like

typhoid fever Typhoid fever, also known simply as typhoid, is a disease caused by '' Salmonella enterica'' serotype Typhi bacteria, also called ''Salmonella'' Typhi. Symptoms vary from mild to severe, and usually begin six to 30 days after exposure. Often th ...

and

cholera Cholera () is an infection of the small intestine by some Strain (biology), strains of the Bacteria, bacterium ''Vibrio cholerae''. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea last ...

.Reece, R.J. (1907). "Report on the Epidemic of Enteric Fever in the City of Lincoln, 1904-5." In ''Thirty-Fifth Annual Report of the Local Government Board, 1905-6: Supplement Containing the Report of the Medical Officer for 1905-6''. Published by the Local Government Board, London.

Composition

The active agent in liquid bleach is

, which gives the product a light greenish yellow tinge and its characteristic chlorine smell. Formulations for household use usually contain 8% or less of sodium hypochlorite by weight, although more concentrated solutions of up to 50% are available for industrial use. Concentrated solutions present serious safety risks. Solid anhydrous sodium hypochlorite is unstable and decomposes explosively. A non-explosive hydrated solid is available for laboratory use, but must be kept refrigerated to avoid decomposition. Liquid bleach usually contains also some

(caustic soda or soda lye, ), intended to keep the solution

alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...

Sodium chloride Sodium chloride , commonly known as Salt#Edible salt, edible salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. It is transparent or translucent, brittle, hygroscopic, and occurs a ...

(table salt, ) is often present too, and plays no role in the product's action. Sodium chloride and hydroxide are normal residues from the main production processes.

References

{{reflist Cleaning products