Hydroxide sodium

Sodium hydroxide (SO-dee-um hye-DROK-side) is a white deliquescent solid commercially available as sticks, pellets, lumps, chips, or flakes. A deliquescent material is one that absorbs moisture from the air. Sodium hydroxide also reacts readily with carbon dioxide in the air to form sodium carbonate. Sodium hydroxide is the most important commercial caustic. A caustic material is a strongly basic or alkaline material that irritates or corrodes living tissue. The compound ranked number n among chemicals produced in the United States in 2004. 

Sodium hydroxide is produced commercially simultaneously with chlorine gas by the electrolysis of a sodium chloride solution. In this process, an electric current breaks down sodium chloride into its component elements, sodium and chlorine. The chlorine escapes as a gas, while the sodium metal form reacts with water to form sodium hydroxide  

Sodium hydroxide. Red atom is oxygen white atom is hydrogen and turquoise atom is sodium, publishers 

Sodium hydroxide can also be produced easily by means of other chemical reactions. For example, the reaction between slaked lime (calcium hydroxide Ca(0H)2) and soda ash (sodium carbonate Na2C03) produces sodium hydroxide  

None of these alternative methods can compete economically, however, with the preparation by electrolysis. 

CHEMICAL NAME = sodium hydroxide CAS NUMBER = 1310-73-2 MOLECULAR FORMULA = NaOH MOLAR MASS = 40.0 g/mol COMPOSITION = Na(57.5°/o) 0(40%) H(2.5%) 

Sodium hydroxide is the most widely used strong base in the chemical industry. It exists as a white, odorless, crystalline solid at room temperature. Sodium hydroxide is a highly corrosive and toxic substance and is called caustic soda or lye. Sodium hydroxide is used as an alkali in the production of numerous products including detergents, paper, synthetic fabrics, cosmetics, and pharmaceuticals. It is the ingredient in many common cleaners, degreasers, drain cleaners, and personal care products. 

Watts work laid the foundation for the current electrolysis method used to produce sodium hydroxide. This method was developed independently during the 1880s by the American chemist Hamilton Young Castner (1858- 1899) and the Austrian chemist Karl Kellner (1850-1905). Castner left Columbia University before graduating and developed a method to produce sodium more economically for use in the aluminum industry. Until the late 1800s, aluminum was considered a precious metal because it was difficult to obtain it in 

Castner turned his interest to gold extraction, which required high-quality sodium hydroxide. Castner developed a three-chambered electrolytic cell. The two end chambers contained brine and graphite electrodes. The middle chamber held water. The cells were separated excepted for a small opening on the bottom, which contained a pool of mercury that served as the cell s cathode. When current flowed through the cell and the cell was rocked, sodium reduced from the brine came into contact with water in the middle cell to produce a sodium hydroxide solution. As Castner built his mercury cell, Kellner was working on a similar design. Rather than compete with each other, Castner and Kellner joined forces to establish the Castner-Kellner Alkali Company to produce sodium hydroxide, which competed with soda ash and potash as an industrial base, and chlorine, which was used primarily to make bleach. 

Contemporary mercury cells are based on the original designs of Castner and Kellner. Mercury is used as the cathode. Sodium produced forms an amalgam, which passes to a water chamber. Here graphite is used to catalyze the dissociation of sodium from the mercury. The sodium reacts with water to produce sodium hydroxide according to the reaction 2Na(s) + 2H — 2NaOH. + H. .. 

The traditional route to sodium hydroxide involved the causticisation of soda ash (Na2C03) with slaked lime [31.22]. This route has largely been superseded by the electrolysis of brine to produce chlorine and caustic soda. However, several companies operating the ammonia soda process or with access to natural sodium carbonate still use the causticisation route [31.23]. 

The process involves reacting a hot solution containing about 12 % of sodium carbonate with quicklime. 

The precipitated calcium carbonate is removed by filtration and the resulting caustic soda solution is concentrated by evaporation. Impurities that precipitate during the concentration process, mainly sodium chloride and sulfate are removed. Most of the caustic soda is marketed as a 50 % solution. 

In most processes, the precipitated calcium carbonate is a waste product. It does not meet the stringent requirements for PCC. At least one company calcines the precipitate and re-uses the resulting quicklime [31.23]. 

Ibe use of slaked lime to regenerate caustic soda by causticising sodium carbonate is a feature of a number of other processes (e.g. the Bayer alumina process — section 31.15 and the processing of carbolic oil [31.24]). 

As the phosphate fiber product required more and more fine tuning, raw material quality became a greater issue. Sodium hydroxide is a manufactured chemical and is usually of high quality, though more expensive than soda ash or Trona. Trona is a mined product and is usually less pure than either sodium hydroxide or soda ash. Its formula is Na3H(C03)2-2H20, a double salt. Trona can be further purified if it is required sodium hydroxide will probably continue to be the reagent of choice. 

DOT Label Corrosive Material, UN 1823 (for solid) and UN 1824 (for solution) Formula NaOH MW 39.998 CAS [1310- 

Synonyms caustic soda sodium hydrate soda lye white caustic 

Caustic soda is one of the most widely used chemicals. It is used to neutralize acids to make sodium salts to precipitate metals as their hydroxides in petroleum refining in the saponification of esters in the treatment of cellulose, plastics, and rubber and in numerous synthetic and analytical applications. 

White translucent crystalline solid (flakes or beads) odorless bitter in taste hygroscopic mp 318°C (604 F) bp 1390 C (2534 F) density 2.10 for pure solid and 1.53 for 50% aqueous solution highly soluble in water (109 g/dL at 20°C (68°F)), aqueous solutions highly alkaline (pH 13 for a 0.1 M solution). 

Sodium hydroxide is a highly corrosive substance that causes damage to human tissues. 

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Heavy metals often can be removed effectively by chemical precipitation in the form of carbonates, hydroxides, or sulfides. Sodium carbonate, sodium bisulfite, sodium hydroxide, and calcium oxide are all used as precipitation agents. The solids precipitate as a floe containing a large amount of water in the structure. The precipitated solids need to be separated by thickening or filtration and recycled if possible. If recycling is not possible, then the solids are usually disposed of to a landfill. 

It is prepared by the action of sodium hydroxide and sodium hypochlorite on phthalimide (Hofmann reaction). When heated with soda lime it gives aniline. 

Castner-Kellner cell An electrolytic cell for the production of sodium hydroxide. ... 

Claisen reaction Condensation of an aldehyde with another aldehyde or a ketone in the presence of sodium hydroxide with the elimination of water. Thus benzaldehyde and methanal give cinnamic aldehyde, PhCH CH-CHO. 

Diethylamine, CH3CH2)2NH. B.p. 55-5°C. Forms a crystalline i hydrate. Prepared by the action of a boiling solution of sodium hydroxide on nitrosodielhylaniline. Forms crystalline compounds with many metallic chlorides. 

CH3CH2OCH2CH2OH. A colourless liquid with a pleasant odour b.p. 135 C. Manufactured by heating ethylene oxide with ethanol and a catalyst, or by treating ethylene glycol with diethyl sulphate and sodium hydroxide. Used extensively as a solvent in nitrocellulose lacquers. 

C12H9N3O4. A brownish-red powder, soluble in sodium hydroxide. Used for the detection and estimation of magnesium, with which it forms a blue lake in alkaline solutions. 

Colourless prisms m.p. 130 C. Manufactured by treating maleic anhydride with water. It is converted to the anhydride by heating at By prolonged heating at 150 "C or by heating with water under pressure at 200 C, it is converted to the isomeric (trans) fumaric acid. Reduced by hydrogen to succinic acid. Oxidized by alkaline solutions of potassium permanganate to mesotartaric acid. When heated with solutions of sodium hydroxide at 100 C, sodium( )-malate is formed. Used in the preparation of ( )-malic acid and in some polymer formulations. 

Dimeihylamine, C2H7N, (CH3)2NH. Colourless, inflammable liquid with an ammoniacal odour, mp -96" C, b.p. 7°C. Occurs naturally in herring brine. Prepared in the laboratory by treating nitrosodimetbyl-aniline with a hot solution of sodium hydroxide. Dimethylamine is largely used in the manufacture of other chemicals. These include the solvents dimethylacetamide and dimethyl-formamide, the rocket propellant unsym-metrical dimethylhydrazine, surface-active agents, herbicides, fungicides and rubber accelerators. 

It reduces to 4-aminodimethylaniline and gives dimethylamine with hot sodium hydroxide solution. It is prepared by the action of nitrous acid upon dimethylaniline at 0 C. 

Both of these chlorohydrins are converted to 1,2-dihydroxypropane by heating with solutions of sodium hydrogen carbonate when heated with solid sodium hydroxide they give 1,2-epoxypropane. U.S. production 1976 4400 tonnes. 

C12H4CI4O2. A by-product in the preparation of 2,4,5-trichlorophenol from 1,2,4,5-tetrachlorobenzene, sodium hydroxide and ethylene glycol. Causes chloracne in humans. 

Trichloroethylene is not attacked by dilute acids or alkalis, but when heated with sodium hydroxide under pressure it yields sodium gly-collate. In the presence of light and oxygen dichloroethanoyl chloride is formed, which can react with any moisture present to give small amounts of highly corrosive HCl. Numerous stabilizers have been patented. 

Sodium hydroxide with stearic acid they constitute the sodium greases, used in the lubrication of bearings under dry conditions and gear trains. 

It is quite clear, first of all, that since emulsions present a large interfacial area, any reduction in interfacial tension must reduce the driving force toward coalescence and should promote stability. We have here, then, a simple thermodynamic basis for the role of emulsifying agents. Harkins [17] mentions, as an example, the case of the system paraffin oil-water. With pure liquids, the inter-facial tension was 41 dyn/cm, and this was reduced to 31 dyn/cm on making the aqueous phase 0.00 IM in oleic acid, under which conditions a reasonably stable emulsion could be formed. On neutralization by 0.001 M sodium hydroxide, the interfacial tension fell to 7.2 dyn/cm, and if also made O.OOIM in sodium chloride, it became less than 0.01 dyn/cm. With olive oil in place of the paraffin oil, the final interfacial tension was 0.002 dyn/cm. These last systems emulsified spontaneously—that is, on combining the oil and water phases, no agitation was needed for emulsification to occur. 

By analogy, ammonium salts should behave as acids in liquid ammonia, since they produce the cation NH4 (the solvo-cation ), and soluble inorganic amides (for example KNHj, ionic) should act as bases. This idea is borne out by experiment ammonium salts in liquid ammonia react with certain metals and hydrogen is given off. The neutralisation of an ionic amide solution by a solution of an ammonium salt in liquid ammonia can be carried out and followed by an indicator or by the change in the potential of an electrode, just like the reaction of sodium hydroxide with hydrochloric acid in water. The only notable difference is that the salt formed in liquid ammonia is usually insoluble and therefore precipitates. 

The hydroxides M (OH)2 are generally less soluble and are of lower base strength. The Group I hydroxides are almost unique in possessing good solubility—most metal hydroxides are insoluble or sparingly soluble hence sodium hydroxide and, to a lesser extent potassium hydroxide, are widely used as sources of the hydroxide ion OH" both in the laboratory and on a large scale. 

Sodium hydroxide is manufactured by electrolysis of concentrated aqueous sodium chloride the other product of the electrolysis, chlorine, is equally important and hence separation of anode and cathode products is necessary. This is achieved either by a diaphragm (for example in the Hooker electrolytic cell) or by using a mercury cathode which takes up the sodium formed at the cathode as an amalgam (the Kellner-Solvay ceW). The amalgam, after removal from the electrolyte cell, is treated with water to give sodium hydroxide and mercury. The mercury cell is more costly to operate but gives a purer product. 

REACTIONS OF THE ELEMENTS WITH ALKALIS (SODIUM HYDROXIDE)... 

Amorphous boron and the amphoteric elements, aluminium and gallium, are attacked by aqueous solutions of sodium hydroxide and... 

Addition of ammonium hydroxide to a solution of an aluminium salt gives a white gelatinous precipitate of aluminium hydroxide, Al(OH)3, insoluble in excess. Sodium hydroxide gives the same precipitate, but in this case, it does dissolve in excess. 

Why is potassium aluminium sulphate not soluble in benzene A compound M has the composition C = 50.0% H=12.5%o A1 = 37.5%. 0.360 g of M reacts with an excess of water to evolve 0.336 1 of gas N and leave a white gelatinous precipitate R. R dissolves in aqueous sodium hydroxide and in hydrochloric acid. 20 cm of N require 40 cm of oxygen for complete combustion, carbon dioxide and water being the only products. Identify compounds N and R, suggest a structural formula for M, and write an equation for the reaction of M with water. (All gas volumes were measured at s.t.p.)... 

Lead dissolves only very slowly in hot concentrated sodium hydroxide and forms hexahydroxoplumbate(II) ... 

Although carbon monoxide appears to be the anhydride of methanoic acid it does not react with water to give the acid however, it will react with sodium hydroxide solution above 450 K, under pressure, to give sodium methanoate ... 

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