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 ?
When is used NaOH and an oxygen pressure, the conversion from 5-HMF to HFCA is achieved.
In contrast, different compressive strength curves and development of the compressive strength were observed in the samples activated with the high molar NaOH activator (5M NaOH).
The optimal condition for the pretreatment was obtained when OPMF was pretreated with 6% of NaOH at 70degC which yielded around 20g/L sugar.
Thermal stability was found higher for 15% NaOH treated fibre followed by 5 %NaOH treated fibre, 10 % NaOH treated fibre and untreated fibre.
Based on statistical test of the data in Figure 1 shows, that the difference in concentrations of NaOH and the time of soaking and interaction not significant effect on the water content.
Analisis termo gravimetrico: En la figura 2 se muestran los resultados del analisis termogravimetrico de las muestra de CH, CH tratada con NaOH y CaCO3 comercial.
FTIR spectra of gelatin from the skins of goat pretreated with NaOH under different conditions are shown in Figure 2.
The pretreatment conditions tested were temperatures of 40-80 [degrees]C, reaction times of 3-5 h under sonication, and NaOH concentrations of 3-6% (w/ w) at a fixed solid-to-liquid ratio, where the experimental conditions of 20 combinations of the three variables were designed.
En este caso las variables independientes varian en los siguientes intervalos: flujo masico de NaOH de 70 kg/h-90 kg/h y flujo masico de ADBS entre 300 kg/h-330 kg/h; para ambos el paso es 5,00 kg/h.
Other than that, the maximum concentration for leaching process is at 1% whereas the surface area of aluminium dross decreases when the concentration increases due to saturation of aluminium dross at higher NaOH concentration [11].