Bleaching Household bleach is, in general, a solution containing 3–8%<unk> , by weight, and 0.01–0.05%<unk>  hydroxide; the<unk>  hydroxide is used to slow the decomposition of<unk>  into<unk>  chloride and<unk>  chlorate. Cleaning<unk>  has destaining properties. Among other applications, it can be used to remove mold stains, dental stains caused by fluorosis, and stains on crockery, especially those caused by the tannins in tea. It has also been used in laundry detergents and as a surface cleaner. It is also used in<unk>  washes. Its bleaching, cleaning, deodorizing and caustic effects are due to oxidation and hydrolysis (saponification). Organic dirt exposed to<unk>  becomes water-soluble and non-volatile, which reduces its odor and facilitates its removal. Disinfection<unk>  in solution exhibits broad spectrum anti-microbial activity and is widely used in healthcare facilities in a variety of settings. It is usually diluted in water depending on its intended use. "Strong chlorine solution" is a 0.5% solution of<unk>  (containing approximately 5000 ppm free chlorine) used for disinfecting areas contaminated with body fluids, including large blood spills (the area is first cleaned with detergent before being disinfected). It may be made by diluting household bleach as appropriate (normally 1 part bleach to 9 parts water). Such solutions have been demonstrated to inactivate both C. difficile and HPV. "Weak chlorine solution" is a 0.05% solution of<unk>  used for washing hands, but is normally prepared with calcium<unk>  granules. "Dakin's Solution" is a disinfectant solution containing low concentration of<unk>  and some boric acid or<unk>  bicarbonate to stabilize the pH. It has been found to be effective with<unk>  concentrations as low as 0.025%. US government regulations allow food processing equipment and food contact surfaces to be sanitized with solutions containing bleach, provided that the solution is allowed to drain adequately before contact with food, and that the solutions do not exceed 200 parts per million (ppm) available chlorine (for example, one tablespoon of typical household bleach containing 5.25%<unk> , per gallon of water). If higher concentrations are used, the surface must be rinsed with potable water after sanitizing. A similar concentration of bleach in warm water is used to sanitize surfaces prior to brewing of beer or wine. Surfaces must be rinsed with sterilized (boiled) water to avoid imparting flavors to the brew; the chlorinated byproducts of sanitizing surfaces are also harmful. The mode of disinfectant action of<unk>  is similar to that of hypochlorous acid. Solutions containing more than 500 ppm available chlorine are corrosive to some metals, alloys and many thermoplastics (such as acetal resin) and need to be thoroughly removed afterwards, so the bleach disinfection is sometimes followed by an ethanol disinfection. Liquids containing<unk>  as the main active component are also used for household cleaning and disinfection, for example toilet cleaners. Some cleaners are formulated to be viscous so as not to drain quickly from vertical surfaces, such as the inside of a toilet bowl. The undissociated (nonionized) hypochlorous acid is believed to react with and inactivate bacterial and viral enzymes. Neutrophils of the human immune system produce small amounts of<unk>  inside phagosomes, which digest bacteria and viruses. Deodorizing<unk>  has deodorizing properties, which go hand in hand with its cleaning properties. Waste water treatment<unk>  solutions have been used to treat dilute cyanide waste water, such as electroplating wastes. In batch treatment operations,<unk>  has been used to treat more concentrated cyanide wastes, such as silver cyanide plating solutions. Toxic cyanide is oxidized to cyanate (OCN−) that is not toxic, idealized as follows: :CN− + OCl− → OCN− + Cl−<unk>  is commonly used as a biocide in industrial applications to control slime and bacteria formation in water systems used at power plants, pulp and paper mills, etc., in solutions typically of 10–15% by weight. Endodontics<unk>  is the medicament of choice due to its efficacy against pathogenic organisms and pulp digestion in endodontic therapy. Its concentration for use varies from 0.5% to 5.25%. At low concentrations it dissolves mainly necrotic tissue; at higher concentrations it also dissolves vital tissue and additional bacterial species. One study has<unk> own that Enterococcus faecalis was still present in the dentin after 40 minutes of exposure of 1.3% and 2.5%<unk> , whereas 40 minutes at a concentration of 5.25% was effective in E. faecalis removal. In addition to higher concentrations of<unk> , longer time exposure and warming the solution (60 °C) also increases its effectiveness in removing soft tissue and bacteria within the root canal chamber. 2% is a common concentration as there is less risk of an iatrogenic<unk>  incident. A<unk>  incident is an immediate reaction of severe pain, followed by edema, haematoma, and ecchymosis as a consequence of the solution escaping the confines of the tooth and entering the periapical space. This may be caused by binding or excessive pressure on the irrigant syringe, or it may occur if the tooth has an unusually large apical foramen. Nerve agent neutralization At the various nerve agent (chemical warfare nerve gas) destruction facilities throughout the United States, 50%<unk>  is used to remove all traces of nerve agent or blister agent from Personal Protection Equipment after an entry is made by personnel into toxic areas. 50%<unk>  is also used to neutralize any accidental releases of nerve agent in the toxic areas. Lesser concentrations of<unk>  are used in similar fashion in the Pollution Abatement System to ensure that no nerve agent is released in furnace flue gas. Reduction of skin damage Dilute bleach baths have been used for decades to treat moderate to severe eczema in humans, but it has not been clear why they work. According to work published by researchers at the Stanford University School of Medicine in November 2013, a very dilute (0.005%) solution of<unk>  in water was successful in treating skin damage with an inflammatory component caused by radiation therapy, excess sun exposure or aging in laboratory mice. Mice with radiation dermatitis given daily 30-minute baths in bleach solution experienced less severe skin damage and better healing and hair regrowth than animals bathed in water. A molecule called nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is known to play a critical role in inflammation, aging, and response to radiation. The researchers found that if NF-κB activity was blocked in elderly mice by bathing them in bleach solution, the animals' skin began to look younger, going from old and fragile to thicker, with increased cell proliferation. The effect diminished after the baths were stopped, indicating that regular exposure was necessary to maintain skin thickness.
Sodium hypochlorite
Amylmetacresol
Sodium hydroxide
Povidone-iodine
Tetrachlorodecaoxide
Chloroethane
Denatured alcohol
Silver nitrate