Aqueous solutions of acids

Since free protons cannot exist, acidic properties can only be shown when the solvent can act as a proton acceptor, i.e. as a base. Thus aqueous solutions of acids contain the hydroxonium ion,... 

H3O" is strictly the oxonium ion actually, in aqueous solutions of acid this and Other solvated-proton structures exist, but they are conveniently represented as... 

In general, polycarbonate resins have fair chemical resistance to aqueous solutions of acids or bases, as well as to fats and oils. Chemical attack by amines or ammonium hydroxide occurs, however, and aUphatic and aromatic hydrocarbons promote crazing of stressed molded samples. Eor these reasons, care must be exercised in the choice of solvents for painting and coating operations. Eor sheet appHcations, polycarbonate is commonly coated with a sihcone—sihcate hardcoat which provides abrasion resistance as well as increased solvent resistance. Coated films are also available. 

Sulfuric Acid. Sulfuric acid is a primary active material of the battery. It must be present to provide sufficient sulfate ions during discharge and to retain suitable conductivity. Lead—acid batteries generally use an aqueous solution of acid in either a free-flowing or in an immobilized state. 

The resins are resistant to aqueous solutions of acids and alkalis and have a wide range of resistance to solvents. Amongst suitable solvents are methylene dichloride, dimethylformamide and phenol. The films bond well to poly-esterimide resins. 

The following are some of the typical industrial applications for liquid-phase carbon adsorption. Generally liquid-phase carbon adsorbents are used to decolorize or purify liquids, solutions, and liquefiable materials such as waxes. Specific industrial applications include the decolorization of sugar syrups the removal of sulfurous, phenolic, and hydrocarbon contaminants from wastewater the purification of various aqueous solutions of acids, alkalies, amines, glycols, salts, gelatin, vinegar, fruit juices, pectin, glycerol, and alcoholic spirits dechlorination the removal of... 

The corrosion resistance of low-alloy steels is not significantly better than that of mild steel for aqueous solutions of acids, salts, etc. The addition of 0.5% copper forms a rust-colored film preventing further steel deterioration small amounts of chromium (1%) and nickel (0.5%) increase the rust... 

The formation of a layer of metal oxide on the surface of this steel provides better corrosion resistance in oxidizing environments than under reducing conditions. Common steels 304, 304L, 347, 316 and 316L are used for equipment exposed to aqueous solutions of acids and other low-temperature corrosive conditions. For high-temperature regimes involving... 

This has a very high resistance to impact damage, even at subzero temperatures. It has good creep strength in dry conditions up to 115°C but degrades by continuous exposures to water hotter than 65°C. It is resistant to aqueous solutions of acids, aliphatic hydrocarbons, paraffins, alcohols (except methanol), animal and vegetable fats and oils, but is attacked by alkalis, ammonia, aromatic and chlorinated hydrocarbons. 

A stable material in humid conditions at temperatures up to 105°C, polyphenylene oxide is resistant to most aqueous solutions of acids and alkalis but is attacked by many organic solvents, particularly by aromatics and chlorinated aliphatics. 

Used at temperatures up to 140°C, polysulfone has good resistance to aqueous solutions of acids and alkalis it is satisfactory with aliphatic solvents but is swollen by aromatics and stress cracked by several organic solvents, including acetone, ethyl acetate, trichlorethylene and carbon tetrachloride. 

The US Bureau of Mines found the chemical and galvanic corrosion behaviour of both the TZM and Mo-30W alloy to be generally equal or superior to that of unalloyed molybdenum in many aqueous solutions of acids, bases and salts. Notable exceptions occurred in 6-1 % nitric acid where both alloys corroded appreciably faster than molybdenum. In mercuric chloride solutions the TZM alloy was susceptible to a type of crevice corrosion which was not due to differential aeration. The alloys were usually not adversely affected by contact with dissimilar metals in galvanic couple experiments, but the dissimilar metals sometimes corroded galvanically. Both alloys were resistant to synthetic sea water spray at 60°C. 

Aqueous solutions of acids as used in metal cleaning processes such as pickling for the removal of rust or rolling scale during the production and fabrication of metals, or in the post-service cleaning of metal surfaces. 

Most organic substances can be dissolved readily in a suitable organic solvent and some are directly soluble in water or can be dissolved in aqueous solutions of acids (basic materials) or of alkalis (acidic materials). Many inorganic substances can be dissolved directly in water or in dilute acids, but materials such as minerals, refractories, and alloys must usually be treated with a variety of reagents in order to discover a suitable solvent in such cases the preliminary qualitative analysis will have revealed the best procedure to adopt. Each case must be considered on its merits no attempt at generalisation will therefore be made. It is however of value to discuss the experimental technique of the simple process of solution of a sample in water or in acids, and also the method of treatment of insoluble substances. 

Phosphoric acid esters are strong acids similar to orthophosphoric acid. Potentiometric titration of a 0.1 N aqueous solution of an acid phosphoric acid ester clearly shows two potential jumps which lie at pH values of 6.5 and 11.5. The pH value of diluted aqueous solutions of acid esters lies in the range of 1-3. Phosphoric acid esters are stable against hydrolysis, but adducts of free phosphoric acid esters with ethylene oxide are generally less stable. 

The phosphate bonded cements described in this chapter are the products of the simple acid-base reaction between an aqueous solution of orthophosphoric acid and a basic oxide or silicate. Such reactions take place at room temperature. Excluded from this chapter are the cementitious substances that are formed by the heat treatment of aqueous solutions of acid metal phosphates. 

Aqueous solutions of acids, bases, and salts are the ionic conductors used most widely and studied most thoroughly. The importance of other types of ionic conductors has increased in recent times, but aqueous solutions are still preeminent. Their significance goes far beyond electrochemistry as such they can be found in practically all spheres of human activity. They are of exceptional importance in the... 

Electrolytes are highly important components of all galvanic cells and electrochemical devices. In most electrochemical devices, such as electrolyzers, batteries, and the like, aqueous solutions of acids and salts are used as electrolytes. Aqueous solutions are easy to prepare, convenient to handle, and as a rule are made from readily available, relatively inexpensive materials. By changing the composition and concentration of the components, it is relatively easy to adjust the specific conductance and other physicochemical properties of these aqueous solutions. 

Acids were an early exception to the no water rule. It was recognized that aqueous solutions of acids would inhibit swelling of clays and shales as well as dissolve any acid-soluble minerals contained in a formation. By 1933 commercial well stimulation with hydrochloric acid was of great interest. A whole separate methodology and treatment chemistry has since evolved around acidizing and fracture acidizing(54). Water emulsions, mainly emulsified acids, and gelled acids thickened with polymeric additives were applied early in the history of well treatment. 

In studying the properties of solutions of substances such as HC1 and HN03, Arrhenius was led to the idea that the acidic properties of the compounds were due to the presence of an ion that we now write as H30+ in the solutions. He therefore proposed that an acid is a substance whose water solution contains H30+. The properties of aqueous solutions of acids are the properties of the H30+ ion, a solvated proton (hydrogen ion) that is known as the hydronium ion in much of the older chemical literature but also referred to as the oxonium ion. 

The blends are water insoluble [47], They can swell in different solvents water, acetone, aqueous solutions of acids and alkalis [47],... 

A ring-chain equilibrium displaced in favor of the cyclic tautomer was observed [78JBC(253)5407 83LA1623] in neutral aqueous solutions of 5-carbamido- 66 n = 3 Xt = 5.67) and 5-guanidino-2-oxovaleric 67 n = 3 Xt = 3.17) acids. In aqueous solutions of acid 67 (w = 3), H-NMR spectroscopy detected the presence of 4% of the open-chain tautomer hydrate 67A (n = 3). In acidic medium, the amount of this hydrate is higher. The dipolar cyclic structure of 67B (n = 3) in the solid state was established on the basis of X-ray diffraction data [83AX(C)1240]. Both isomers 67A and... 

Aqueous solutions of acidic metal salts are usually inherently unstable and hydrolyze readily to oxides (the hydroxides of these metals tend to be relatively unstable), in some cases forming films. Such hydrolysis can be more readily controlled by adding boric acid to fluoro-complexes of the metal, e.g. ... 

Chloro-triaquo-diammino-cobaltic Sulphate, [Co(NH3)2(H30)3 Ci]S04.H.,0, is obtained by decomposing an aqueous solution of acid dichloro-diaquo-diammino-cobaltic sulphate, [Co(b IIg)2(H20)2Cl2]S04H, with a small quantity of sulphuric acid and evaporating the solution in vacuo. It separates in indigo-coloured crystals and is soluble in water, giving a blue solution. 

Hammett acidity function, H0, for aqueous solutions of acids, fData tiom R.A. Cox and K. Yates, "Acidity Functions. Can. J. Chem. 1983, 61,2225.]... 

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