When was sodium hypochlorite discovered?
Sodium hypochlorite has a long history. Around 1785 the Frenchman Berthollet developed liquid bleaching agents based on sodium hypochlorite. The Javel company introduced this product and called it ‘liqueur de Javel’. At first, it was used to bleach cotton. Because of its specific characteristics it soon became a popular compound. Hypochlorite can remove stains from clothes at room temperature. In France, sodium hypochlorite is still known as ‘eau de Javel’.
Sodium hypochlorite is a clear, slightly yellowish solution with a characteristic odor.
Sodium hypochlorite has a relative density of is 1,1 (5,5% watery solution).
As a bleaching agent for domestic use it usually contains 5% sodium hypochlorite (with a pH of around 11, it is irritating). If it is more concentrated, it contains a concentration 10-15% sodium hypochlorite (with a pH of around 13, it burns and is corrosive).
Sodium hypochlorite is unstable. 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. Sodium hypochlorite is a strong oxidator and reacts with flammable compounds and reductors. Sodium hypochlorite solution is a weak base that is inflammable.
These characteristics must be kept in mind during transport, storage and use of sodium hypochlorite.
What is sodium hypochlorite?
Sodium hypochlorite (NaOCl), commonly known as bleach, is a solution made from reacting chlorine with a sodium hydroxide solution, also referred to as caustic. These two reactants are the major co-products of most chlor-alkali cells.
What is the chemical formula for sodium hypochlorite?
The chemical compound formula for sodium hypochlorite is NaOCl.
Reacting chlorine and sodium hydroxide will produce sodium hypochlorite:
Cl2 + 2NaOH = NaOCl + NaCl + H2O
What are the applications of sodium hypochlorite?
Sodium hypochlorite is used on a large scale. For example in agriculture, chemical industries, paint- and lime industries, food industries, glass industries, paper industries, pharmaceutical industries, synthetics industries and waste disposal industries. In the textile industry sodium hypochlorite is used to bleach textile. It is sometimes added to industrial waste water. This is done to reduce odors. Hypochlorite neutralizes sulphur hydrogen gas (SH) and ammonia (NH3). 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.
Properties and applications
- bactericidal, antiseptic, oxidising and corrosive properties;
- production of household chemicals;
- used as a bleaching agent in the textile and pulp and paper industries;
- cleaning and disinfection of drinking water;
- domestic and industrial waste treatment, removal of organic and inorganic pollutants;
- disinfection of systems, pipelines, and tanks in the dairy industry;
- in the food industry used in wine production and brewing;
- fungicidal and germicidal treatment of grains;
- disinfection of technical rooms;
- in medicine and pharmacy as an antiviral, antifungal, and bactericidal agent;
- raw material in industrial organic synthesis;
- reagent for photometric tests;
- production of modified food starch;
Physical properties of 10 sodium hypochlorite
- The molar mass of 10 sodium hypochlorite is 74.4 g/mol.
- The melting point of the pentahydrate form of sodium hypochlorite is 18°C. While on decomposition, the boiling point of sodium hypochlorite solution is 101℃.
- Its pentahydrate form is a greenish-yellow solid.
- Sodium hypochlorite is soluble in water with a density of 1.11 g/cm³.
- Due to its high reactivity, it is highly corrosive.
- It has a chlorine-like and sweetish odour.
- Sodium hypochlorite is explosive and unstable, although sodium hypochlorite pentahydrate is non-explosive and stable at lower temperatures.
Sodium Hypochlorite Hazards/Precautions
- Never mix Sodium Hypochlorite, with acidic solutions or Ammonia. Doing so forms a dangerous gas potentially leading to choking and breathing difficulty.
- Avoid swallowing and getting sodium hypochlorite in the eyes or on the skin. Depending on the strength of sodium hypochlorite, severity can range from mild irritation to severe burns.
- In the event sodium hypochlorite is swallowed, seek emergency help immediately. If the affected person is alert, give them milk or water to drink. Do not induce vomiting. Seek immediate medical attention.
- Skin or eyes should be immediately flushed continuously and thoroughly if coming into contact with sodium hypochlorite. Seek immediate medical attention.
- In the event of inhalation of sodium hypochlorite, leave the affected area and seek fresh air. If breathing is difficult, administer oxygen and seek immediate medical attention.
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