Sodium hydrate NaOH

Digestion The coarsely ground bauxite is treated with a sodium hydroxide (NaOH) solution at 150-160 C and 0.5 MPa total pressure. Most of the hydrated alumina goes into solution as sodium aluminate ... 

CAS 1310-73-2 EINECS/ELINCS 215-185-5 UN 1823 (DOT) 1824 (DOT) INS524 E524 Synonyms Caustic soda Lye Soda lye Sodium hydrate White caustic Classification Alkali hydroxide Empincai HNaO Formuia NaOH... 

Aluminum is the most commercially important nonferrous metal. Its chemistry and uses will be discussed in Section 27-7. Aluminum is obtained from bauxite, or hydrated aluminum oxide, AI2O3 XH2O. Aluminum ions can be reduced to A1 by electrolysis only in the absence of H2O. First the crushed bauxite is purified by dissolving it in a concentrated solution of sodium hydroxide, NaOH, to form soluble Na[Al(OH)4].Then Al(OH)3 XH2O is precipitated from the filtered solution by blowing in carbon dioxide to neutralize the... 

Sodium hydroxide (NaOH) has a lattice energy of —887 kJ/mol and a heat of hydration of -932 kJ/mol. How much solution could be heated to boiling by the heat evolved by the dissolution of 25.0 g of NaOH (For the solution, assume a heat capacity of... 

Crystallizes from water in large colourless prisms containing 2H2O. It is poisonous, causing paralysis of the nervous system m.p. 101 C (hydrate), 189°C (anhydrous), sublimes 157°C. It occurs as the free acid in beet leaves, and as potassium hydrogen oxalate in wood sorrel and rhubarb. Commercially, oxalic acid is made from sodium methanoate. This is obtained from anhydrous NaOH with CO at 150-200°C and 7-10 atm. At lower pressure sodium oxalate formed from the sodium salt the acid is readily liberated by sulphuric acid. Oxalic acid is also obtained as a by-product in the manufacture of citric acid and by the oxidation of carbohydrates with nitric acid in presence of V2O5. 

Sodium metaborate tetrahydrate can be prepared by cooling a solution containing borax and an amount of sodium hydroxide just in excess of the theoretical amount. The dihydrate is prepared by United States Borax Chemical Corp. by mixing appropriate quantities of borax penta- or decahydrate hydrate and aqueous NaOH to give a 46 to 52% solution concentration of Na20 20 (107). The mixture is then heated to about 90°C to dissolve all soHds and slowly cooled to 60—75°C. Crystals of the dihydrate ate then harvested and dried. 

A mixture of 3-hydroxy-4-phenylfurazan and 1,2,4-oxadiazole 243 was prepared from a-phenyl-a-hydroximino hydroxamic acid by acylation and subsequent treatment with 15% aqueous NaOH (Scheme 164) (25G201). The reaction of tetraacetate 244 with sodium acetate hydrate in glacial acetic acid at 70°C gives 3,4-dihydroxyfurazan (9%) (92URP1752734). a-Hydroximino ester 245 reacts with hydroxylamine to form furazan 246 in 25% yield (Scheme 164) (79JHC689). 

Reaction of o-toluidine with chloral hydrate in presence of hydroxylamine hydrochloride and subsequent treatment with H2SO4 gave the isatin derivative 337. Bromination of 337 followed by reaction with sodium diethyl malonate gave 338. Catalytic reduction with Pd/C gave the oxoindole derivative 339 that upon hydrolysis with aqueous NaOH followed by... 

Hydrated RuCl, (1.5 g, ca. 6.2 mmol) is stirred with sodium periodate (5.5 g, 26 mmol) in H20 (50 ml) for 12 h. The precipitated ruthenium oxide is added at 0-5°C under an atmosphere of oxygen to aqueous TPA-OH (1M, 5 ml) and aqueous NaOH (0.8 M, 50 ml). Precipitated TPA-Ru04 (87%) is collected and washed well with H20 and dried under vacuum. 

Substances typical of acids and bases are, respectively, HCl and NaOH. Hydrogen chloride dissolves in water with practically complete dissociation into hydrated protons and hydrated chloride ions. Sodium hydroxide dissolves in water to give a solution containing hydrated sodium ions and hydrated hydroxide ions. Table 3.6 gives values of the mean ionic activity coefficients, y , at different concentrations and indicates the pH values and those expected if the activity coefficients are assumed to be unity. 

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