Basic solutions solubility

Histones—strongly basic solutions, soluble in water... 

Coatings, Paints, and Pigments. Various slightly soluble molybdates, such as those of zinc, calcium, and strontium, provide long-term corrosion control as undercoatings on ferrous metals (90—92). The mechanism of action presumably involves the slow release of molybdate ion, which forms an insoluble ferric molybdate protective layer. This layer is insoluble in neutral or basic solution. A primary impetus for the use of molybdenum, generally in place of chromium, is the lower toxicity of the molybdenum compound. 

Vitamin is iasoluble ia water and is soluble ia 70% alcohol, cbloroform, petroleum ether, ben2ene, and hexane. Vitamin is stable ia air but should be protected from light. Although unstable ia alkaU, the vitamin is stable ia acidic medium. Its facile decomposition ia basic solution forms the basis of the Dam-Karrer color test. 

Antimony trioxide is insoluble in organic solvents and only very slightly soluble in water. The compound does form a number of hydrates of indefinite composition which are related to the hypothetical antimonic(III) acid (antimonous acid). In acidic solution antimony trioxide dissolves to form a complex series of polyantimonic(III) acids freshly precipitated antimony trioxide dissolves in strongly basic solutions with the formation of the antimonate ion [29872-00-2] Sb(OH) , as well as more complex species. Addition of suitable metal ions to these solutions permits formation of salts. Other derivatives are made by heating antimony trioxide with appropriate metal oxides or carbonates. 

In general, hydrated borates of heavy metals ate prepared by mixing aqueous solutions or suspensions of the metal oxides, sulfates, or halides and boric acid or alkali metal borates such as borax. The precipitates formed from basic solutions are often sparingly-soluble amorphous soHds having variable compositions. Crystalline products are generally obtained from slightly acidic solutions. 

SolubiHty is used in the refining of oilseed meals to give protein isolates and concentrates (18). Proteins are highly soluble in basic solutions and the... 

The solubility of AS2O3 in water, and the species present in solution, depend markedly on pH. In pure water at 25°C the solubility is 2.16 g per lOOg this diminishes in dilute HCl to a minimum of 1.56g per lOOg at about 3 m HCl and then increases, presumably due to the formation of chloro-complexes. In neutral or acid solutions the main species is probably pyramidal As(OH)3, arsenious acid , though this compound has never been isolated either from solution or otherwise (cf. carbonic acid, p. 310). The solubility is much greater in basic solutions and spectroscopic evidence points to... 

Ammonia is one of the most important inorganic chemicals, exceeded only by sulfuric acid and lime. This colorless gas has an irritating odor, and is very soluble in water, forming a weakly basic solution. Ammonia could be easily liquefied under pressure (liquid ammonia), and it is an important refrigerant. Anhydrous ammonia is a fertilizer by direct application to the soil. Ammonia is obtained by the reaction of hydrogen and atmospheric nitrogen, the synthesis gas for ammonia. The 1994 U.S. ammonia production was approximately 40 billion pounds (sixth highest volume chemical). 

The extent of hydrolysis of (MY)(n 4)+ depends upon the characteristics of the metal ion, and is largely controlled by the solubility product of the metallic hydroxide and, of course, the stability constant of the complex. Thus iron(III) is precipitated as hydroxide (Ksal = 1 x 10 36) in basic solution, but nickel(II), for which the relevant solubility product is 6.5 x 10 l8, remains complexed. Clearly the use of excess EDTA will tend to reduce the effect of hydrolysis in basic solutions. It follows that for each metal ion there exists an optimum pH which will give rise to a maximum value for the apparent stability constant. 

Sodium carbonate is a white, powdery solid moderately soluble in water to give a basic solution. It reacts with acids to produce a sodium salt and carbon dioxide. 

The strong base is a soluble hydroxide that ionizes completely in water, so the concentration of OH matches the 0.25 M concentration of the base. For the weak base, in contrast, the equilibrium concentration of OH is substantially smaller than the 0.25 M concentration of the base. At any instant, only 0.8% of the ammonia molecules have accepted protons from water molecules, producing a much less basic solution in which OH is a minor species. The equilibrium concentration of unproton-ated ammonia is nearly equal to the Initial concentration. Figure 17-7 summarizes these differences. 

A second separation technique is leaching, which uses solubility properties to separate the components of an ore. For example, modem gold production depends on the extraction of tiny particles of gold from gold-bearing rock deposits. After the rock is crushed, it is treated with an aerated aqueous basic solution of sodium cyanide. Molecular oxygen oxidizes the metal, which forms a soluble coordination complex with the cyanide anion ... 

Bauxite, the main aluminum ore, is a mixed oxide-hydroxide, A1(0)0H, contaminated with Si02, Fc2 O3, clay, and other hydroxide salts. To isolate the aluminumcontaining material, the ore is treated with a strongly basic solution, whose high hydroxide concentration causes the solid to dissolve as a soluble complex ion,... 

Aluminas. Aluminas, porous AI2O3, are available in many forms. They constitute the most important carrier material in heterogeneous catalysis. Alumina is amphoteric and, as a con.sequence, soluble in both acidic and basic media. Precipitation can be performed from an acid solution by adding a base or from a basic solution by adding an acid, as schematically represented in Fig. 3.18. If, for example, at a pH of less than about 3 a base is added to an aqueous solution of aluminium sulphate, a precipitate is formed. If this material is filtered, dried and calcined, an amorphous porous AI2O3 is obtained. At other pH values different porous aluminas can be synthesized. 

Solution pH is an important variable, as it controls solubility, the deposition potential, and precursor speciation [140], As noted, one of the advantages of using an ALE process is that very different solutions can be used for each step in the cycle. For instance, pH 4 Cd solutions have been used with pH 10 Te solutions to form CdTe. Some care must be taken rinsing between solutions, however. On the other hand, Foresti et al. have used the same pH for both the metal and chalcogenide in the formation of II-VI compounds, such as CdS and CdSe on Ag single crystals [115, 116, 123, 143], To keep the Cd from precipitating in the basic solution, they complexed it with pyrophosphate. 

The anion of the soluble salt hydrolyzes to form a basic solution CH3COO- + H20 CH3COOH + OH-... 

Inorganic components in soil are extracted with water, acidic solutions containing highly soluble ligands and chelates, and basic solutions. Acidic solutions are typically used for extraction of metals and metal ions in both exchangeable and nonexchangeable forms. Basic solutions are used much less commonly, although they are important for oxyanions, particularly phosphate. 

This starch derivative is a water-soluble polymer of D-glucose with a largely helical structure. Therefore, like cyclodextrins, it has the ability to bind alkyl chains and to catalyse reactions through the involvement of ionized hydroxyl groups in basic solution (Hui et al., 1982 Cheng et al., 1985). 

A fractionation procedure has been established and widely applied to studies of humic materials [42-44]. The procedure begins with natural OM (i.e., humus) and uses an aqueous basic solution (e.g., 0.1-0.5 mol/1 NaOH and Na2C03) to solubilize a fraction of the OM. The basic extract is then acidified which causes a precipitate to form, i.e., humic acids (HA). The fraction, which remains in solution, is called fulvic acids (FA). Humin is the name given to the insoluble organic fraction that remains after extraction of humic and fulvic acids. At nearneutral pH (pH 5 - 8), which is characteristic of most natural water, the FA are the most water soluble of these three fractions. HA are somewhat less soluble, with their solubility increasing as the pH increases. Humin is insoluble at all pH values. 

The chromate anion is a highly soluble, toxic tetrahedral complex (point group Tj) that occurs in oxidized, neutral-basic solutions. It is also one of a small number of aqueous complexes that have been thoroughly characterized by spectroscopic measurements on numerous isotopic compositions (Muller and Kbniger 1974), so it will be possible to check the vibrational model against real data. Here the MUBFF is applied under the assumption that aqueous chromate can be approximately modeled as a gas-phase molecule. 

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