LATEST:- SODIUM

History

(English, soda; Medieval Latin, sodanum: a headache remedy) Long recognized in compounds, sodium was first isolated by Davy in 1807 by electrolysis of caustic soda.

Sources

Sodium is present in fair abundance in the sun and stars. The D lines of sodium are among the most prominent in the solar spectrum. Sodium is the fourth most abundant element on earth, comprising about 2.6% of the earth's crust; it is the most abundant of the alkali group of metals.

It is now obtained commercially by the electrolysis of absolutely dry fused sodium chloride. This method is much cheaper than that of electrolyzing sodium hydroxide, as was used several years ago.

Compounds

The most common compound is sodium chloride (table salt), but it occurs in many other minerals, such as soda niter, cryolite, amphibole, zeolite, etc.

Properties

Sodium, like every reactive element, is never found free in nature. Sodium is a soft, bright, silvery metal which floats on water. Decomposition in water results in the evolution of hydrogen and the formation of the hydroxide. It may or may not ignite spontaneously on water, depending on the amount of oxide and metal exposed to the water. It normally does not ignite in air at temperatures below 115oC.

Uses

Metallic sodium is vital in the manufacture of esters and in the preparation of organic compounds. The metal may be used to improve the structure of certain alloys, descale metal, and purify molten metals.

An alloy of sodium with potassium, NaK, is an important heat transfer agent.

Compounds

Sodium compounds are important to the paper, glass, soap, textile, petroleum, chemical, and metal industries. Soap is generally a sodium salt of certain fatty acids. The importance of common salt to animal nutrition has been recognized since prehistoric times.

Among the many compounds that are of the greatest industrial importance are common salt (NaCl), soda ash (Na2CO3), baking soda (NaHCO3), caustic soda (NaOH), Chile saltpeter (NaNO3), di- and tri-sodium phosphates, sodium thiosulfate (hypo, Na2S2O3 . 5H2O), and borax (Na2B4O7 . 10H2O).

Isotopes

Thirteen isotopes of sodium are recognized.

Cost

Metallic sodium is priced at about 15 to 20 cents/lb in quantity. Reagent grade (ACS) sodium in January 1990 cost about $35/lb. On a volume basis, it is the cheapest of all metals.

Handling

Sodium metal should be handled with great care. It cannot be maintained in an inert atmosphere and contact with water and other substances with which sodium reacts should be avoided.

Ammonium nitrate

The chemical compound ammonium nitrate, the nitrate of ammonia with the chemical formula NH₄NO₃, is a white crystalline solid at room temperature and standard pressure. It is commonly used in agriculture as a high-nitrogen fertilizer, and it has also been used as an oxidizing agent in explosives, including improvised explosive devices.

Ammonium nitrate is used in cold packs, as hydrating the salt is an endothermic process.

Production

The processes involved in the production of ammonium nitrate in industry, although chemically simple, are technologically challenging. The acid-base reaction of ammonia with nitric acid gives a solution of ammonium nitrate:^[3] HNO₃(aq) + NH₃(g) → NH₄NO₃(aq). For industrial production, this is done using anhydrous ammonia gas and concentrated nitric acid. This reaction is violent and very exothermic. After the solution is formed, typically at about 83% concentration, the excess water is evaporated to an ammonium nitrate (AN) content of 95% to 99.9% concentration (AN melt), depending on grade. The AN melt is then made into "prills" or small beads in a spray tower, or into granules by spraying and tumbling in a rotating drum. The prills or granules may be further dried, cooled, and then coated to prevent caking. These prills or granules are the typical AN products in commerce.

The Haber process combines nitrogen and hydrogen to produce ammonia, part of which can be oxidised to nitric acid and combined with the remaining ammonia to produce the nitrate. Another production method is used in the so-called Odda process.

Sodium

Sodium (pronounced /ˈsoʊdiəm/) is an element which has the symbol Na (Latin natrium, from Arabic natrun), atomic number 11, atomic mass 23 [g/mol], and a common oxidation number +1. Sodium is a soft, silvery white, highly reactive element and is a member of the alkali metals within "group 1" (formerly known as ‘group IA’). It has only one stable isotope, ²³Na. Sodium was first isolated by Sir Humphry Davy in 1806 by passing an electric current through molten sodium hydroxide. Sodium quickly oxidizes in air and is violently reactive with water, so it must be stored in an inert medium, such as kerosene or mineral oil. Sodium is present in great quantities in the Earth's oceans as sodium chloride (common salt). It is also a component of many minerals, and it is an essential element for animal life. As such, it is classified as a “dietary inorganic macro-mineral.”

Chemical properties

Compared with other alkali metals, sodium is generally less reactive than potassium and more reactive than lithium,^[2] in accordance with "periodic law": for example, their reaction in water, chlorine gas, etc.;

Sodium reacts exothermically with water: small pea-sized pieces will bounce across the surface of the water until they are consumed by it, whereas large pieces will explode. While sodium reacts with water at room temperature, the sodium piece melts with the heat of the reaction to form a sphere, if the reacting sodium piece is large enough. The reaction with water produces very caustic sodium hydroxide (lye) and highly flammable hydrogen gas. These are extreme hazards (see Precautions section below). When burned in air, sodium forms sodium peroxide Na₂O₂, or with limited oxygen, the oxide Na₂O (unlike lithium, the nitride is not formed). If burned in oxygen under pressure, sodium superoxide NaO₂ will be produced. In chemistry, most sodium compounds are considered soluble but nature provides examples of many insoluble sodium compounds such as the feldspars. There are other insoluble sodium salts such as sodium bismuthate NaBiO₃, sodium octamolybdate Na₂Mo₈O₂₅• 4H₂O, sodium thioplatinate Na₄Pt₃S₆, sodium uranate Na₂UO₄. Sodium meta-antimonate's 2NaSbO₃•7H₂O solubility is 0.3g/L as is the pyro form Na₂H₂Sb₂O₇• H₂O of this salt. Sodium metaphosphate NaPO₃ has a soluble and an insoluble form