Insolubility in acids and bases

Calcined alumina, a-Al202, and naturally occurring comndum are practically insoluble in acids and bases, but partially calcined and low temperature amorphous oxide, such as that which forms on nacent commercial aluminum surfaces, is soluble... 

Compound A is a brown, water-soluble solid. When dissolved in a solution of KI, A yields a white precipitate, J5, and a red-brown solution C. B is insoluble in acids and bases, but dissolves in aqueous NaCN, the resulting solution yielding a red precipitate, Z), upon treatment with Zn dust. 

Solution C becomes colorless upon treatment with excess base, but reacidification causes the red-brown color to return. If C is acidified and saturated with H2S, the color fades, and yellow precipitate, F, is formed. F is insoluble in acids and bases. 

Diamond 2.40 100 5,000 (0.2-100 im) 7,000 insoluble in water, insoluble in acids and bases, extremely hard... 

Wohler and Streicher,13 however, have prepared the dichloride by ignition of iridium trichloride in chlorine at 770° C., and thus placed its existence beyond all doubt. It is a crystalline substance, brown in colour, and insoluble alike in acids and bases. Its limits of stability axe 763° to 773° C. in an atmosphere of chlorine. Above 773° C. it dissociates into the monochloride and free chlorine. 

The metal is not attacked by mineral acids at room temperature or even by hot aqueous alkali. It dissolves in hot HC1, giving Ti111 species, whereas hot HN03 converts it into a hydrous oxide that is rather insoluble in acid or base. The best solvents are HF or acids to which fluoride ions have been added. Such media dissolve Ti and hold it in solution as fluoro complexes. 

Properties Black amorphous material. D 8.342, decomposes on heating. Insoluble in water soluble in acids and bases. 

The isolated substances were similar to marine fulvic acids. Tripalmitin gave no product and in fact never dissolved. The products were pale yellow powders soluble in acid and base but insoluble in ether or methylene chlo-... 

The classic definitions of soil humic and fulvic acids are based on solubility (Schnitzer and Khan, 1972). Thus, humic acid is the alkali-soluble material in soil, which is precipitated at pH 1. The material which remains soluble in the extract at pH 1 is fulvic acid. A more recent definition for aquatic humic substances is given by Thurman and Malcolm (1981). Here the material which adsorbs on an XAD column from an acid aqueous solution is defined as aquatic humus. That part of the adsorbed material which is soluble in acid and base is fulvic acid the portion insoluble in acid is humic acid. Another definition of an aquatic humic substance is based on adsorption by DEAE-cellulose columns (Miles etal., 1983). 

Of the complexes prepared, only the trinitro complex is stable toward water. This compound is relatively insoluble in organic solvents, as well as in water. Hydrolysis to form the more stable hydroxo or aquo complexes occurs with the trithiocyanato and trichloro complexes. The compound [Co(dien)(SCN)2(OH)] has the rather remarkable property of being insoluble in acids and soluble in bases it can be recovered from basic solution by precipitation with acids. 

Cupric azide Cu(N3)2 forms several basic salts that are described in Table 4.8 [15]. Basic cupric azides are insoluble in water and undergo hydrolysis above 80 °C. They are soluble in acids and bases [5, 15],... 

In neutral solutions (4-8 pH), the hydroxide is insoluble which makes aluminum surhice passive. Aluminum dissolves both in acids and bases. 

Thal/iumifll) oxide, TI2O3. Dark solid obtained by Tl plus O2 or Tl(III) salt plus base. Insoluble in water and alkalis but dissolves in acid (often gives T1(I) salts). 

Iron(II) hydroxide [18624-44-7], Fe(OH)2, is prepared by precipitation of an iron(II) salt solution by strong base in the absence of air. It occurs as pale green, hexagonal crystals or a white amorphous powder. It is practically insoluble in water, fairly soluble in ammonium salt solutions, and soluble in acids and in concentrated NaOH solution. It is slowly oxidized by air. Conversion to Fe203 atH20 is eventually complete. 

Iron(III) hydroxide [1309-33-7], FeH02, is a red-brown amorphous material that forms when a strong base is added to a solution of an iron(III) salt. It is also known as hydrated iron(III) oxide. The fully hydrated Fe(OH)3 has not been isolated. The density of the material varies between 3.4-3.9 g/cm, depending on its extent of hydration. It is insoluble in water and alcohol, but redissolves in acid. Iron(III) hydroxide loses water to form Fe203. Iron(III) hydroxide is used as an absorbent in chemical processes, as a pigment, and in abrasives. Salt-free iron(III) hydroxide can be obtained by hydrolysis of iron(III) alkoxides. 

Lead antimonate [13510-89-9] (Naples yellow), Pb2(Sb0 2> mol wt 993.07, d = 6.58g/cm, is an orange-yeUow powder that is insoluble in water and dilute acids, but very slightly soluble in hydrochloric acid. Lead antimonates are modifiers for ferroelectric lead titanates, pigments in oil-base paints, and colorants for glasses and glazes (see Colorants for ceramics). They are made by the reaction of lead nitrate and potassium antimonate solutions, followed by concentration and crystallization. 

As normally polymerized, PVF melts between IH5 and 210 °C and contains 12 18% inverted monomer units ft is normally considered a thermoplastic, but because of its instability above its melting point, it cannot be processed by conventional thermoplastic techniques Instead it is generally extruded into films in a solvent swollen (organosol) form and the solvent is subsequently evaporated and recovered Such films can be onented further to achieve specific mechanical properties PVF films are exceptionally weather and radiabon resistant considenng their modest fluonne content PVF is insoluble below 100 °C but, at higher temperatures, it dissolves in polar solvents like amides, ketones, tetramethylene sulfone, and tetramethylurea Resistance to acids and bases at room temperature IS good [1, 29 ... 

Ethane, like methane, is a colorless gas that is insoluble in water. It does not react with acids and bases, and is not very reactive toward many reagents. It can also be partially oxidized to a carbon monoxide and hydrogen mixture or chlorinated under conditions similar to those used... 

Amino acid zwitterions are internal salts and therefore have many of the physical properties associated with salts. They have large dipole moments, are soluble in water but insoluble in hydrocarbons, and are crystalline substances with relatively high melting points. In addition, amino acids are amphiprotic they can react either as acids or as bases, depending on the circumstances. In aqueous acid solution, an amino acid zwitterion is a base that accepts a proton to yield a cation in aqueous base solution, the zwitterion is an add that loses a proton to form an anion. Note that it is the carboxylate, -C02-, that acts as the basic site and accepts a proton in acid solution, and it is the ammonium cation, -NH3+, that acts as the acidic site and donates a proton in base solution. 

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