Today, most chlorine is produced through the electrolysis of aqueous sodium chloride NaCl. Chlorine is commonly used as an antiseptic and is used to make drinking water safe and to treat swimming pools. Large amounts of chlorine are used in many industrial processes, such as in the production of paper products, plastics, dyes, textiles, medicines, antiseptics, insecticides, solvents and paints.
Two of the most familiar chlorine compounds are sodium chloride NaCl and hydrogen chloride HCl. Sodium chloride, commonly known as table salt, is used to season food and in some industrial processes. Hydrogen chloride, when mixed with water H 2 O , forms hydrochloric acid, a strong and commercially important acid.
Chlorine is a very dangerous material. Liquid chlorine burns the skin and gaseous chlorine irritates the mucus membranes. Its properties ensure it finds a multitude of applications even though it is a highly dangerous substance. Most of us encounter chlorine every day, often without realising it. What is its history, where can we find it and how is it produced?
Read the first part of our feature on chlorine to find out. Chlorine in its pure form was discovered in by Carl Wilhelm Scheele, a chemist of German and Swedish ancestry. It was produced in a reaction of manganese IV oxide with hydrochloric acid.
Initially Carl Scheele thought he had discovered a compound that contained oxygen. Liquid chlorine was only produced in by English chemist Michael Faraday.
From that moment on, chlorine became a permanent feature of many fields of life, finding numerous applications.
In common perception, chlorine compounds are mainly known for their presence in nature, where the element is found only as the chloride ion Cl — , constituting 0. They are particularly common in the oceans. Chloride ions constitute about 1.
They can also be found in salty lake waters and in underground brine deposits. Minerals that contain chlorine include sylvine potassium chloride , halite rock salt , and carnalite double potassium magnesium chloride hydrate. Over different chlorine-based chemical compounds are also naturally present among living organisms. Chlorine is also present in the human body. Chlorine compounds can be found, for example, in the skin, blood, teeth, and tears. Chlorine contained in white blood cells aids in fighting infections.
We can also find chloride ions in hydrochloric acid , which is a digestion enzyme present in the stomach. Let us take a closer look at this element, however. Free chlorine occurs in the form of a typical, two-atom molecule Cl 2. In compounds, on the other hand, it occurs at oxidation states from -I to VII. It is a chemically active element, which combines with hydrogen to produce hydrogen chloride under the effect of scattered sunlight. Under the right conditions it also binds with other elements, forming various chlorides.
We can produce chlorine under laboratory conditions, e. In the U. This plant used a cell equipped with an asbestos diaphragm developed by Ernest A. LeSueur from Canada. By , the estimated yearly capacity of all commercial plants in the U. These figures do not include the U. Army's Edgewood, Maryland Arsenal plant's annual chlorine gas production capacity of 36, tons.
In his report on the Economics of Chlorine, D. Pritchard concludes "The [chlor-alkali] industry in North America has had to manufacture and sell cheaply, find markets and new uses, switch largely from bleaching powder to liquid chlorine, provide technical service, and adjust more or less imperfectly the economics of three distinct substances evolved in one major operation to a rapidly changing industrial structure, and do it all in about 16 years.
A capacity bearing a reasonable relation to consumption, a decent return on its capital, and the continuance of research are essential to this key industry. In January , when Eben C.
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