sodium hydroxide


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sodium hydroxide,

chemical compound, NaOH, a white crystalline substance that readily absorbs carbon dioxide and moisture from the air. It is very soluble in water, alcohol, and glycerin. It is a causticcaustic,
any strongly corrosive chemical substance, especially one that attacks organic matter. A caustic alkali is a metal hydroxide, especially that of an alkali metal; caustic soda is sodium hydroxide, and caustic potash is potassium hydroxide.
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 and a strong base (see acids and basesacids and bases,
two related classes of chemicals; the members of each class have a number of common properties when dissolved in a solvent, usually water. Properties
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). Commonly known as caustic soda, lye, or sodium hydrate, it is available commercially in various solid forms, e.g., pellets, sticks, or chips, and in water solutions of various concentrations; both solid and liquid forms vary in purity. The major use of sodium hydroxide is as a chemical and in the manufacture of other chemicals; because it is inexpensive, it is widely used wherever a strong base is needed. It is also used in producing rayon and other textiles, in making paper, in etching aluminum, in making soaps and detergents, and in a wide variety of other uses. The principal method for its manufacture is electrolytic dissociation of sodium chloride; chlorine gas is a coproduct. Small amounts of sodium hydroxide are produced by the soda-lime process in which a concentrated solution of sodium carbonate (soda) is reacted with calcium hydroxide (slaked lime); calcium carbonate precipitates, leaving a sodium hydroxide solution.

Sodium Hydroxide

 

(caustic soda, soda lye), NaOH, a caustic alkali; colorless crystals. Density, 2.13 g/cm3; melting point, 320°C. The industrial product is an opaque, white solid mass with a radial fracture. Sodium hydroxide is hygroscopic; a large amount of heat is liberated upon its reaction with water. Aqueous solutions of NaOH exhibit a strong alkaline reaction. The solubility of sodium hydroxide in water is 52.2 percent at 20°C and 75.8 percent at 80°C. It forms crystal hydrates, such as NaOH-H2O, which is stable at ordinary temperatures (12.3°-61.8°C). Upon exposure to air, NaOH absorbs CO2 and is converted into sodium carbonate. Sodium hydroxide has a destructive effect on skin, paper, and other materials; even very small quantities of NaOH cause extremely severe damage upon contact with the eyes.

Sodium hydroxide is prepared by electrolysis of NaCl solutions or by boiling a Na2 CO3solution with milk of lime: Na2C03+ Ca (OH)2 CaC03+ 2NaOH. The sodium hydroxide solution is evaporated, and the residue is heated to the melting point and then poured into molds. Electrolysis yields chlorine in addition to NaOH. Sodium hydroxide is one of the main products of the modern chemical industry; it is widely used both in the chemical industry and in many other sectors.

sodium hydroxide

[′sōd·ē·əm hī′dräk‚sīd]
(inorganic chemistry)
NaOH White, deliquescent crystals; absorbs carbon dioxide and water from air; soluble in water, alcohol, and glycerol; melts at 318°C; used as an analytical reagent and chemical intermediate, in rubber reclaiming and petroleum refining, and in detergents. Also known as sodium hydrate.

sodium hydroxide

a white deliquescent strongly alkaline solid used in the manufacture of rayon, paper, aluminium, soap, and sodium compounds. Formula: NaOH
References in periodicals archive ?
Obstructive airway disease associated with occupational sodium hydroxide inhalation.
In all the experiments, fish scales solution was titrated against primary standard HCl for determination of the unconsumed base in order to know that how much sodium hydroxide has been utilized during hydrolysis.
Figures 1, 2, 3, and 4 are the nitrogen adsorption and desorption isotherms for raw aluminium dross and treated with 1% concentration of sodium hydroxide, stirring time of 30 minutes, and leaching temperatures of 25[degrees]C, 40[degrees]C, and 55[degrees]C, respectively.
The other issue is under pressure cell that have the ability to produce liquid chlorine gas of electrolysis, the ability to produce sodium hydroxide 50% or solid sodium hydroxide.
This paper presents results of an investigation on the the characterization of sodium hydroxide (NaOH) in causticization processes, and its influence on the reactive dyeing of lyocell fabric by exhaust, pad-dry-cure and pad-batch methods.
The platinum blade evidently removed from the flame even more heat than the sodium hydroxide, but it, however, radiated even more.
Chitin measurement: The highest chitin content was for culture containing 120 g/ kg DM sodium hydroxide treated rice straw (P <0.
The sodium hydroxide and the sodium silicate solutions were first mixed with each other and stirred to obtain a homogeneous mixture of the solutions before adding them to the solids.
At the ethanol factory, furthermore, a part of cellulose that is a raw material for fuel alcohol is poured in sodium hydroxide to produce sodium nitrate, which is used for removing calcium in the seawater and facilitating the molten-salt electrolysis of sodium or magnesium (Murahara and Seki, 2007).
The document says Spencer signed an agreement with the state in 1990 that allowed the town to treat its water pipes with sodium hydroxide, but the approval was contingent on Spencer maintaining a functioning alarm system that would notify someone of a problem.
The Environment Agency confirmed they had advised on the removal of the sodium hydroxide, and a spokeswoman for Wirral Council said the local authority would "use the full force of the law to protect its local environment".