Basically, sodium hypochlorite “breaks down into many different chemicals” once it is added to the water. Two of those chemicals are hypochlorous acid and hypochlorite ions, which both destroy bacteria and oxidize the water.
Is sodium hypochlorite a solid liquid or gas?
Sodium hypochlorite Sodium hypochlorite is chlorine gas dissolved in sodium hydroxide. This is essentially household bleach. Sodium hypochlorite is a disinfectant that is liquid at room temperature and can be dosed with chemical feed pumps. Hypochlorite chemistry Na+ OCl– + H 2 O ——> H+ OCl– + Na+ OH– Hypochlorite (OCl–) is the ...
When to use sodium hypochlorite?
Sodium hypochlorite in a dilute form is commonly known as bleach. It is a household chemical compound widely used as a bleaching agent or a disinfectant. Sodium hypochlorite is among the oldest, most important, and most widely used chlorine based bleaches.
How do you neutralize sodium hypochlorite?
- If you’ve used alkali peroxide—which is popular for lightening the color of wood—you will want to neutralize with white vinegar. ...
- When bleaching with oxalic acid, which is good for removing stains such as iron, you want to use baking soda as a neutralizer. ...
- Chlorine bleach used on wood only needs to be rinsed several times with distilled water.
What is the common use of sodium hypochlorite?
The Cautions of the Uses of Sodium Hypochlorite
- Glucose Oxidation Blocker In 1948, Knox was reported the idea of glucose oxidation blocking as the main factor in natural bactericide chlorine solution. ...
- Block the DNA Replication Recently is reported that the bacteria inactivation by hypochlorite occurs due to the blocking of DNA replication. ...
- Outspread Protein and Aggregation
Can hypochlorite be oxidized?
The hypochlorite oxidation process is known to start by a single-electron oxidation, producing the ClO• radical (reaction (1) in Scheme 1). (24) Formation of the ClO• radical initiates a complex reaction sequence in which the system can follow different reaction pathways.
Is sodium hypochlorite an oxidizing?
Sodium hypochlorite is a strong oxidizer. Oxidation reactions are corrosive.
How does sodium hypochlorite degrade?
Factors that promote sodium hypochlorite decomposition are heat, light, metal ions (including water hardness), low pH (less than 11), and soil. This decomposition rate is exponential, not linear, so a significant amount of the decomposition occurs in the first week after production.
Why is sodium hypochlorite an oxidizing agent?
Chlorine bleaches are oxidizing agents; when chlorine reacts with water, it produces hydrochloric acid and atomic oxygen. The oxygen reacts easily with the chromophores to remove electrons from the molecule, chemically changing the structure of the molecule and the physical properties that cause the color are changed.
How fast does sodium hypochlorite degrade?
At normal pH (6-8), sodium hypochlorite can degrade substantially within 2-3 weeks.
Does bleach oxidize?
Most household bleaches are based on chlorine and contain sodium hypochlorite (NaClO). This is an oxidizing agent, which causes a reaction to form another chemical compound.
Does sodium hypochlorite break down in sunlight?
Chlorine evaporates at a rate of 0.75 gram per day of active chlorine from solution. Sodium hypochlorite disintegrates when heated or if it contacts acids, sunlight, certain metals, and poisonous and corrosive gases, including chlorine gas.
How long does sodium hypochlorite last for?
After the six-month expiration date, the sodium hypochlorite in bleach begins to degrade, at a rate of about 20 percent per year.
Does sunlight affect sodium hypochlorite?
EXPOSURE TO LIGHT Light speeds up the decomposition of sodium hypochlorite solutions. Modern packaging methods and use of polyethylene bottles have practically eliminated the influence of light on bleach stability. The use of green or amber glass bottles will also materially reduce decomposition caused by light.
Is hypochlorite a strong oxidizer?
Hypochlorite is the strongest oxidizing agent of the chlorine oxyanions. This can be seen by comparing the standard half cell potentials across the series; the data also shows that the chlorine oxyanions are stronger oxidizers in acidic conditions.
How does sodium hypochlorite react with water?
When sodium hypo chlorite dissolves in water, two substances form, which play a role in for oxidation and disinfection. These are hypochlorous acid (HOCl) and the less active hypochlorite ion (OCl-). The pH of the water determines how much hypochlorous acid is formed.
Does NaOCl oxidize primary or secondary alcohols?
NaOCl in acetic acid is a cheap and efficient reagent for the oxidation of secondary alcohols to ketones.
What is the name of the process used to make sodium hypochlorite?
Bottled solutions of sodium hypochlorite were sold under numerous trade names. Today, an improved version of this method, known as the Hooker process (named after Hooker Chemicals, acquired by Occidental Petroleum ), is the only large-scale industrial method of sodium hypochlorite production.
What is the solution used to titrate hypochlorite?
Titration of hypochlorite solutions is often done by adding a measured sample to an excess amount of acidified solution of potassium iodide ( KI) and then titrating the liberated iodine ( I#N#2) with a standard solution of sodium thiosulfate or phenyl arsine oxide, using starch as indicator, until the blue color disappears.
What is the majority of chlorine in a solution?
2. At pH greater than 7.4, the majority is in the form of hypochlorite ClO−. . The equilibrium can be shifted by adding acids (such as hydrochloric acid) or bases (such as sodium hydroxide) to the solution: ClO−.
How to make NaOCl 2 H#N#2O?
A 1966 patent describes the production of solid stable dihydrate NaOCl ·2 H#N#2O by reacting a chloride-free solution of hypochlorous acid HClO (such as prepared from chlorine monoxide ClO and water), with a concentrated solution of sodium hydroxide. In a typical preparation, 255 mL of a solution with 118 g/L HClO is slowly added with stirring to a solution of 40 g of NaOH in water 0 °C. Some sodium chloride precipitates and is removed by fitration. The solution is vacuum evaporated at 40–50 °C and 1–2 mmHg until the dihydrate crystallizes out. The crystals are vacuum-dried to produce a free-flowing crystalline powder.
What is the name of the compound that contains sodium cation?
Sodium hypochlorite (commonly known in a dilute solution as bleach) is a chemical compound with the formula NaOCl or NaClO, comprising a sodium cation ( Na+. ) and a hypochlorite anion ( OCl−. or ClO−. ).
What is bleach used for?
Household bleach sold for use in laundering clothes is a 3–8 % solution of sodium hypochlorite at the time of manufacture. Strength varies from one formulation to another and gradually decreases with long storage. Sodium hydroxide is usually added in small amounts to household bleach to slow down the decomposition of NaClO.
Why do containers explode?
Containers may explode when heated due to release of chlorine gas. Hypochlorite solutions are corrosive to common container materials such as stainless steel and aluminium. The few compatible metals include titanium (which however is not compatible with dry chlorine) and tantalum. Glass containers are safe.
How does sodium hypochlorite affect color?
Increased concentration of sodium hypochlorite can effectively accelerate the colour fading effect. Generally speaking, the active chlorine content in sodium hypochlorite has an optimum value to achieve the best colour fading effect. If the concentration of sodium hypochlorite is higher than this optimum value, no further improvement in colour fading is obtained. The recommended active chlorine content is 12% when concentration of sodium hypochlorite is about 40 g/L. In addition, increase in temperature increases the bleaching reaction to fade the colour from denim garments. The optimum temperature is 70 °C; temperature higher than 70 °C does not enhance colour fading effect ( Hong Kong Apparel Product Development and Marketing Research Center, 2002 ). The pH value used for bleach washing also affects colour fading. When pH = 7 or pH < 7, the bleaching reaction is very fast and the degree of colour fading is very difficult to control. When pH = 9–10 (adjusted by adding alkali), the bleaching effect can be controlled by the bleaching time ( Hong Kong Apparel Product Development and Marketing Research Center, 2002 ).
What is sodium hypochlorite?
Sodium hypochlorite (bleach, CAS 7681-52-9) is an aqueous solution produced by the mixture of chloramine gas and water. It is used as a disinfectant in various settings. Toxicity is dependent on concentration, route, and duration of exposure. Availability in households attributes to frequent exposures. Toxic effects vary from mild irritation to significant tissue damage. Most unintentional exposures result as minor irritation. Intentional ingestions can cause significant burns or strictures of the gastrointestinal tract. Dermal and ocular exposures can cause irritation and corrosive injuries. Sodium hypochlorite combined with an acid or ammonia forms chlorine and chloramine gases, which cause upper respiratory irritation to chemical pneumonitis.
How long can sodium hypochlorite be stored?
Hypochlorite solutions decompose and should not be stored for more than 1 month and must be stored in a cool, dark, dry area. The sodium hypochlorite solution is diluted with water in a mixing/holding tank. The diluted solution is then injected by a chemical pump in to the water supply pipe at a controlled rate.
What enzymes are used to reduce the concentration of hydrogen peroxide?
In order to reduce the concentration of hydrogen peroxide and eliminate alkali and stabilizers from the bleaching baths, enzymes from the oxydoreductase group have been introduced as biocatalysts for oxygenation reactions of coloured impurities of cotton fibres.
How much chlorine is needed for disinfection?
They are typically used at 0.02–0.2% levels of available chlorine for disinfection, and require 1–10 min contact time. Chlorine compounds are inactivated by organic soil, so a cleaning step is often required for heavily soiled surfaces.
What are the remedial measures for hypochlorite?
Remedial measures. the cleaning solution of hypochlorite be made according to the recommended strength. the drainage after cleaning be thoroughly done and no amount of cleaning solution be retained in the vessel. welding be properly controlled and with an inert gas to avoid the formation of a black scale.
Is chlorine a dye?
Chlorine in the form of sodium hypochlorite has long been used for bleaching of textile materials. Water-soluble dyes such as reactive, acid, direct and metal complex dyes are decolorised readily by hypochlorite, but water-insoluble disperse and vat dyes are resistant to decolorisation in this process.40−41 Decolorisation of reactive dyes require long reaction times, while metal complex dye solution remains partially coloured even after an extended period of treatment.
What happens when sodium hypochlorite dissolves in water?
When sodium hypochlorite dissolves in water, two substances are formed that play a role in oxidation and the disinfection processes. These are hypochlorous acid and the less active hypochlorite ion. The pH of the water determines how much hypochlorous acid is formed.
How is sodium hypochlorite made?
Sodium hypochlorite can be produced in two ways. One is by dissolving salt in softened water, resulting in a concentrated brine. This brine is then electrolyzed to form a sodium hypochlorite solution containing 150 grams of active chlorine per liter. During this reaction hydrogen gas is also formed. The chemical also can be produced by adding chlorine gas to caustic soda, producing sodium hypochlorite, water and salt.
Why does chlorine degrade over time?
Right after the sodium hypochlorite is added to water, chlorine levels decline because the chlorine is reacting with organic matter and microbes. After those reactions are complete, chlorine will slowly escape into the air as a gas. For this reason, free and total chlorine levels slowly degrade over time in a container.
What is the active ingredient in bleach?
The community had been using chlorine gas and ammonia as primary and secondary disinfectants. Sodium hypochlorite (NaClO) is the active ingredient in commercial liquid bleach, which is commonly available in 6, 12 and 15 percent solutions.
What is the pH of sodium hypochlorite?
Sodium hypochlorite is a clear, slightly yellowish solution with a characteristic odor. As a bleaching agent it is usually a 5 percent sodium hypochlorite with a pH of about 11. More concentrated solutions (10 to 15 percent) have a pH of about 13. Sodium hypochlorite is unstable.
How much does chlorine evaporate?
Chlorine evaporates at a rate of 0.75 gram per day of active chlorine from solution. Sodium hypochlorite disintegrates when heated or if it contacts acids, sunlight, certain metals, and poisonous and corrosive gases, including chlorine gas.
What are the advantages of salt electrolysis?
The advantage of salt electrolysis system in formation of sodium hypochlorite is that no transport or storage of chemical is required. Another advantage of the on-site process is that chlorine lowers the pH, and no other acid is required to lower pH. The hydrogen gas produced is explosive, and as a result ventilation is required.
What happens when sodium hypochlorite dissolves in water?
When sodium hypo chlorite dissolves in water, two substances form, which play a role in for oxidation and disinfection. These are hypochlorous acid (HOCl) and the less active hypochlorite ion (OCl-).
Why is sodium hypochlorite inactive?
When sodium hypochlorite is stored for a long time, it becomes inactive . Another advantage of the on site process is that chlorine lowers the pH and no other acid is required to lower pH. The hydrogen gas that is produced is explosive and as a result ventilation is required for expolsion prevention.
What is the difference between HCl and HCl?
While sodium hypochlorite is used, hydrochloric acid (HCl) is used to lower the pH. Sulfuric acid (H2SO4) can be used as an alternative for acetic acid.
How is hypochlorous acid made?
Hypochlorous acid is produced by the reaction of sodium hydroxide with chlorine gas. In water, the so-called 'active chlorine' is formed. There are various ways to use sodium hypochlorite. For on-site salt electrolysis, a solution of salt (NaCl) in water is applied. Sodium(Na+) and chloride (Cl-) ions are produced.
How much chlorine evaporates from a solution?
Chlorine evaporates at a rate of 0,75 gram active chlorine per day from the solution. Then heated sodium hypochlorite disintegrates. This also happens when sodium hypochlorite comes in contact with acids, sunlight, certain metals and poisonous and corrosive gasses, including chlorine gas.
Why does chlorine burn?
When there is too much chlorine in the water, this burns the body tissues, which causes damage to air tracts, the stomach and the intestines, the eyes and the skin. When sodium hypochlorite is used in swimming pools, it sometimes causes red eyes and it gives off a typical chlorine odor.
What is hypochlorite used for?
It is also used to detoxify cyanide baths in metal industries. Hypochlorite can be used to prevent algae and shellfish growth in cooling towers. In water treatment, hypochlorite is used to disinfect water. In households, hypochlorite is used frequently for the purification and disinfection of the house.
How is magnesium hypochlorite prepared?
It can be prepared by reaction of hypochlorous acid upon magnesium carbonate in water. However, the product is not stable in water and decomposes to form basic magnesium hypochlorite, Mg (OCl) 2 ·2Mg (OH) 2, which is useful in bleaching and sanitizing applications. The structure of this compound remains unknown.
What is the formula for magnesium hypochlorite?
Magnesium hypochlorite has the chemical formula of Mg (OCl)2 and the molecular weight of 127.286 g/mol. Its assigned CAS number is 10233-03-1. It can be prepared by reaction of hypochlorous acid upon magnesium carbonate in water. However, the product is not stable in water and decomposes to form basic magnesium hypochlorite, Mg (OCl)2 ·2Mg (OH) 2, which is useful in bleaching and sanitizing applications. The structure of this compound remains unknown.
What is NaOCl in laundry?
Sodium hypochlorite (NaOCl) is available in several concentrations, ranging from common household bleach with 5% available chlorine through commercial laundry bleaches that contain 12–15% available chlorine. Bleach solutions contain an excess of alkali that elevates the pH during application of the bleach.
What is the after wash with mineral acid?
Hence an after-wash with mineral acid, termed ‘souring’, is essential to remove such deposits. The same treatment is also used for removal of residual chlorine after sodium hypochlorite bleaching. The material is finally washed to remove traces of acid, which may otherwise form hydrocellulose.
How long to treat residual chlorine after bleaching?
A better method for removal of residual chlorine, particularly after bleaching with sodium hypochlorite, is to treat the material at 40°C for 15 min in liquor containing 2–2.5% (o.w.m.) a reducing agent like sodium sulphite, bisulphite, hydrosulphite or thiosulphate. View chapter Purchase book.
Is bleach a solution?
Household bleach is an aqueous solution of 5.25%–6.15% sodium hypochlorite. Hypochlorites have a broad-spectrum of antimicrobial activity. They do not leave toxic residues, are unaffected by water hardness, are inexpensive and fast acting.
Is bleaching fabric yellowing?
There is a chance of yellowing of bleached fabric on storage. 5. It releases relatively high concentrations of salt in the effluent process water, which is objectionable from an ecological point of view. Two chemical compounds are utilised in hypochlorite bleaching – bleaching powder and sodium hypochlorite.
Is sodium hypochlorite a weak acid?
The effectiveness of sodium hypochlorite in the cleaning and disinfection processes depends on the concentration of available chlorine and the pH of the solution. Hypochlorous acid (HOCl) is a weak acid and dissociates to the hypochlorite ion (-OCl) and proton (H+) depending on the solution pH.
Is sodium hypochlorite a disinfectant?
Sodium hypochlor ite fulfills many requirements as the ideal disinfectant and furthermore it has an excellent cleaning action. The effectiveness of sodium …. Sodium hypochlorite (NaOCl) is the most widely used disinfectant in the food industry despite the increasing availability of other disinfectants.
Overview
Chemistry
Anhydrous sodium hypochlorite can be prepared but, like many hypochlorites, it is highly unstable and decomposes explosively on heating or friction. The decomposition is accelerated by carbon dioxide at atmospheric levels. It is a white solid with the orthorhombic crystal structure.
Sodium hypochlorite can also be obtained as a crystalline pentahydrate NaOCl·5H 2O, which is not explosive and is much more stable than the anhydrous compound. The formula is sometimes gi…
Production
Potassium hypochlorite was first produced in 1789 by Claude Louis Berthollet in his laboratory on the Quai de Javel in Paris, France, by passing chlorine gas through a solution of potash lye. The resulting liquid, known as "Eau de Javel" ("Javel water"), was a weak solution of potassium hypochlorite. Antoine Labarraque replaced potash lye by the cheaper soda lye, thus obtaining sodium hypochlorite (Eau de Labarraque).
Packaging and sale
Household bleach sold for use in laundering clothes is a 3–8% solution of sodium hypochlorite at the time of manufacture. Strength varies from one formulation to another and gradually decreases with long storage. Sodium hydroxide is usually added in small amounts to household bleach to slow down the decomposition of NaClO.
Uses
Household bleach is, in general, a solution containing 3–8% sodium hypochlorite, by weight, and 0.01–0.05% sodium hydroxide; the sodium hydroxide is used to slow the decomposition of sodium hypochlorite into sodium chloride and sodium chlorate.
Sodium hypochlorite 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 c…
Safety
It is estimated that there are about 3,300 accidents needing hospital treatment caused by sodium hypochlorite solutions each year in British homes (RoSPA, 2002).
Sodium hypochlorite is a strong oxidizer. Oxidation reactions are corrosive. Solutions burn the skin and cause eye damage, especially when used in concentrated forms. As recognized by the NFPA, however, only solutions containing more than 40% sodium hypochlorite by weight are considere…
Environmental impact
In spite of its strong biocidal action, sodium hypochlorite per se has limited environmental impact, since the hypochlorite ion rapidly degrades before it can be absorbed by living beings.
However, one major concern arising from sodium hypochlorite use is that it tends to form persistent chlorinated organic compounds, including known carcinogens, that can be absorbed by organisms and enter the food chain. These compounds may be formed during household storag…
See also
• Calcium hypochlorite Ca(OCl) 2 ("bleaching powder")
• Potassium hypochlorite KOCl (the original "Javel water")
• Lithium hypochlorite LiOCl
• Sodium hypochlorite washes