Sodium hypochlorite
Other names	Sodium chlorate(I)
Identifiers
CAS number	7681-52-9
Properties
Molecular formula	NaOCl
Molar mass	74.44 g/mol
Appearance	white solid
Density	1.07-1.14 g/cm^3 liquid
Melting point	18°C Pentahydrate Image File history File links Download high resolution version (1847x1100, 30 KB) File links The following pages link to this file: Sodium hypochlorite User:Benjah-bmm27/Gallery ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... For other uses, see Density (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...
Boiling point	101°C Decomposes Italic text This article is about the boiling point of liquids. ...
Solubility in water	Fully miscible
Hazards
EU classification	Corrosive (C) Dangerous for the environment (N)
R-phrases	R31, R34, R50
S-phrases	S1/2, S28, S45, S50, S61
Related Compounds
Other anions	Sodium chloride Sodium chlorite Sodium chlorate Sodium perchlorate
Other cations	Lithium hypochlorite Calcium hypochlorite
Related compounds	Hypochlorous acid
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Sodium hypochlorite is a chemical compound with the formula NaClO. Sodium hypochlorite solution, commonly known as bleach, is frequently used as a disinfectant and as a bleaching agent. Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances (as amended) is the main European Union law concerning chemical safety. ... R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... This article is about the electrically charged particle. ... R-phrases 36 S-phrases none Flash point Non-flammable Related Compounds Other anions NaF, NaBr, NaI Other cations LiCl, KCl, RbCl, CsCl, MgCl2, CaCl2 Related salts Sodium acetate Supplementary data page Structure and properties n, εr, etc. ... Sodium chlorite is a chemical compound used in the manufacture of paper. ... Sodium chlorate (NaClO3) is an oxidizing agent. ... Sodium perchlorate is a perchlorate of sodium and has the formula NaClO4. ... This article is about the electrically charged particle. ... Lithium is poisonous in natural form usually attacking the CNS or Central Nervous System when touched by bare hand. ... Calcium hypochlorite is a chemical compound with formula Ca(ClO)2. ... Hypochlorous acid is a weak, unstable acid with chemical formula HOCl. ... The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... A chemical compound is a chemical substance of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... This article is about the chemical whitener. ... This is an article about antimicrobial agents. ...

Production

Sodium hypochlorite may be prepared by absorbing chlorine gas in cold sodium hydroxide solution: General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... Flash point Non-flammable. ...

2NaOH + Cl₂ → NaCl + NaClO + H₂O

Sodium hydroxide and chlorine are commercially produced by the chloralkali process, and there is no need to isolate them to prepare sodium hypochlorite. Hence NaClO is prepared industrially by the electrolysis of sodium chloride solution with minimal separation between the anode and the cathode. The solution must be kept below 40 °C (by cooling coils) to prevent the formation of sodium chlorate. The chloralkali process is a redox reaction, an electrolysis of an aqueous solution of sodium chloride: 2 NaCl(aq) + 2 H2O(l) —→ 2 NaOH(aq) + Cl2(g) + 2 H+ + 2 e- 2 H+ + 2 e- —→ H2(g) The process is primarily used to produce chlorine, but one of its byproducts... This article is about the chemical process. ... R-phrases 36 S-phrases none Flash point Non-flammable Related Compounds Other anions NaF, NaBr, NaI Other cations LiCl, KCl, RbCl, CsCl, MgCl2, CaCl2 Related salts Sodium acetate Supplementary data page Structure and properties n, εr, etc. ... Diagram of a zinc anode in a galvanic cell. ... Diagram of a copper cathode in a Daniells cell. ... Sodium chlorate (NaClO3) is an oxidizing agent. ...

The commercial solutions always contain significant amounts of sodium chloride (common salt) as the main byproduct, as seen in the equation above.

Packaging and sale

Household bleach sold for use in laundering clothes is a 3-6% solution of sodium hypochlorite at the time of manufacture. Strength varies from one formulation to another and gradually decreases with long storage. In biology percentage solutions are often preferred to molar ones. ...

A 12% solution is widely^{[citation needed]} used in waterworks for the chlorination of water. High-test hypochlorite (HTH) is sold for chlorination of swimming pools and contains approximately 30% calcium hypochlorite. The crystalline salt is also sold for the same use; this salt usually contains less than 50% of calcium hypochlorite. However, the level of "active chlorine" may be much higher.

It can also be found on store shelves present in "Daily Sanitizing Sprays", as the sole active ingredient at 0.0095%.

Uses

In household bleach form, sodium hypochlorite is used for removal of stains from laundry. It is particularly effective on cotton fiber, which stains easily but bleaches well. 50 to 250 ml per load is usually recommended for a standard-size washer. The properties of household bleach that make it effective for removing stains also result in cumulative damage to organic fibers such as cotton, and the useful lifespan of these materials will be shortened with regular bleaching. The sodium hydroxide (NaOH) that is also found in household bleach (as noted later) causes fiber degradation as well. It is not volatile, and residual amounts of NaOH not rinsed out will continue slowly degrading organic fibers in the presence of humidity. For these reasons, if stains are localized, spot treatments should be considered whenever possible. With safety precautions, post-treatment with weak organic acids such as acetic (vinegar) will neutralize the NaOH, and volatilize the chlorine from residual hypochlorite. Old t-shirts and cotton sheets that rip easily demonstrate the costs of laundering with household bleach. Hot water increases the activity of the bleach, owing to the thermal decomposition of hypochlorite which ultimately generates environmentally-undesirable chlorate. This article is about the chemical whitener. ...

A weak solution of 1% household bleach in warm water is used to sanitize smooth surfaces prior to brewing of beer or wine. Surfaces must be rinsed to avoid imparting flavors to the brew; these chlorinated byproducts of sanitizing surfaces are also harmful.

US Government regulations (21 CFR Part 178) allow food processing equipment and food contact surfaces to be sanitized with solutions containing bleach provided the solution is allowed to drain adequately before contact with food, and the solutions do not exceed 200 parts per million (ppm) available chlorine (for example, one tablespoon of typical household bleach containing 5.25% sodium hypochlorite, per gallon of water). If higher concentrations are used, the surface must be rinsed with potable water after sanitizing.

A 1 in 5 dilution of household bleach with water (1 part bleach to 4 parts water) is effective against many bacteria and some viruses, and is often the disinfectant of choice in cleaning surfaces in hospitals (Primarily in the United States). The solution is corrosive, and needs to be thoroughly removed afterwards, so the bleach disinfection is sometimes followed by an ethanol disinfection. Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... This article is about biological infectious particles. ... For the hazard, see corrosive. ... Grain alcohol redirects here. ...

For shock chlorination of wells or water systems, a 2% solution of household bleach is used. For larger systems, HTH is more practical because lower rates can be used. The alkalinity of the sodium hypochlorite solution also causes the precipitation of minerals such as calcium carbonate, so that the shock chlorination is often accompanied by a clogging effect. The precipitate also preserves bacteria, making this practice somewhat less effective. Shock Chlorination is used in many pools and other water sources to reduce the bacterial residue in the water. ...

Sodium hypochlorite has been used for the disinfection of drinking water, at a concentration equivalent to about 1 liter of household bleach per 4000 liters of water is used. The exact amount required depends on the water chemistry, temperature, contact time, and presence or absence of sediment. In large-scale applications, residual chlorine is measured to titrate the proper dosing rate. For emergency disinfection, the United States Environmental Protection Agency recommends the use of 2 drops of 5%ac household bleach per quart of water. If the treated water doesn't smell of bleach, 2 more drops are to be added. EPA redirects here. ...

The use of chlorine-based disinfectants in domestic water, although widespread, has led to some controversy due to the formation of small quantities of harmful byproducts such as chloroform. R-phrases , , , S-phrases , Flash point Non-flammable U.S. Permissible exposure limit (PEL) 50 ppm (240 mg/m3) (OSHA) Supplementary data page Structure and properties n, εr, etc. ...

It is also used in dentistry, during root canal treatment, disinfecting the canal and dissolving any remaining pulp tissue. Historically, Henry Drysdale Dakin's solution (0.5%) had been used. Nowadays, 2.5-5.25% solutions are being used. This article is about the dental profession. ... Henry Drysdale Dakin (1880 - 1952) was an English chemist. ...

An alkaline solution (pH 11.0) of sodium hypochlorite is used to treat dilute (< 1 g/L) cyanide wastewater, e.g. rinsewater from an electroplating shop. In batch treatment operations, sodium hypochlorite has been used to treat more concentrated cyanide wastes, such as silver cyanide plating solutions. A well-mixed solution is fully treated when an excess of chlorine is detected.

Mechanism of action

See Hypochlorous acid Hypochlorous acid is a weak, unstable acid with chemical formula HOCl. ...

Cautions

Sodium hypochlorite is a strong oxidizer. Products of the oxidation reactions are corrosive. Solutions burn skin and cause eye damage, particularly when used in concentrated forms. However, as recognized by the NFPA, only solutions containing more than 40% sodium hypochlorite by weight are considered hazardous oxidizers. Solutions less than 40% are classified as a moderate oxidizing hazard (NFPA 430, 2000). An oxidizing agent is a substance that oxidizes another substance in electrochemistry or redox chemical reactions in general. ...

Household bleach and pool chlorinator solutions are typically stabilized by a significant concentration of lye (caustic soda, NaOH) as part of the manufacturing reaction. Skin contact will produce caustic irritation or burns due to defatting and saponification of skin oils and destruction of tissue. The slippery feel of bleach on skin is due to this process.

Sodium thiosulfate (hypo) is an effective chlorine neutralizer. Rinsing with a 5mg/L solution, followed by washing with soap and water, quickly removes chlorine odor from the hands. Sodium thiosulfate (Na2S2O3) is a colorless crystalline compound that is more familiar as the pentahydrate, Na2S2O3•5H2O, an efflorescent, monoclinic crystalline substance also called sodium hyposulfite or “hypo. ...

Chlorination of drinking water can oxidize organic contaminants, producing trihalomethanes (also called haloforms), which are carcinogenic. The extent of the hazard thus created is a subject of disagreement. Trihalomethanes (THMs) are chemical compounds in which three of the four hydrogen atoms of methane (CH4) are replaced by halogen atoms. ...

Mixing bleach with some household cleaners can be hazardous. For example, mixing an acid cleaner with sodium hypochlorite bleach generates chlorine gas. Mixing with ammonia solutions (including urine) produces chloramines. Both chlorine gas and chloramine gas are toxic. Bleach can react violently with hydrogen peroxide and produce oxygen gas:^[1] For other uses, see Acid (disambiguation). ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... For other uses, see Ammonia (disambiguation). ... This article or section is in need of attention from an expert on the subject. ... Chloramine (monochloramine) is chemical compound with the formula NH2Cl. ... Toxic redirects here, but this is also the name of a song by Britney Spears; see Toxic (song) Look up toxic and toxicity in Wiktionary, the free dictionary. ... R-phrases , , , , S-phrases , , , ,, , , , Flash point Non-flammable Related Compounds Related compounds Water Ozone Hydrazine Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in...

H₂O_{2 (aqueous)} + NaClO_(aqueous) → NaCl_(aqueous) + H₂O_(liquid) + O_{2 (gas)}

It is estimated that there are about 3300 accidents needing hospital treatment caused by sodium hypochlorite solutions each year in British homes (RoSPA, 2002).

See also

• Chlorination
• Water purification

Chlorination is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water. ... Control room and schematics of the water purification plant to Bret lake. ...

Bibliography

• Jones, F.-L. (1972). "Chlorine poisoning from mixing household cleaners". J. Am. Med. Assoc. 222: 1312. 
• Institut National de Recherche et de Sécurité. (2004). "Eaux et extraits de Javel. Hypochlorite de sodium en solution". Fiche toxicologique n° 157, Paris.

External links

• International Chemical Safety Card 0482 (solutions<10% active Cl)
• International Chemical Safety Card 1119 (solutions >10% active Cl)
• European Chemicals Bureau
• Institut National de Recherche et de Sécurité (in French)
• Home and Leisure Accident Statistics 2002 (UK RoSPA)
• Emergency Disinfection of Drinking Water (United States Environmental Protection Agency)
• Chlorinated Drinking Water (IARC Monograph)
• NTP Study Report TR-392: Chlorinated & Chloraminated Water (US NIH)
• Guidelines for the Use of Chlorine Bleach as a Sanitizer in Food Processing Operations (Oklahoma State University)

EPA redirects here. ... IARC could mean: International Agency for Research on Cancer is part of the World Health Organization. ... NIH can refer to: National Institutes of Health Norwegian School of Sports Sciences: (Norges idrettshøgskole - NIH) Not Invented Here This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...

References

1. ^ Hydrogen Peroxide + Bleach Explanation. Retrieved on 10 April 2007.