Hydrochloric and Sulfuric Acids

Both acids are used in starch and sucrose hydrolyses. Hydrochloric acid is also used in protein hydrolysis in industrial production of seasonings. 

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Niobium Pent chloride. Niobium pentachloride can be prepared in a variety of ways but most easily by direct chlorination of niobium metal. The reaction takes place at 300—350°C. Chlorination of a niobium pentoxide—carbon mixture also yields the pentachloride however, generally the latter is contaminated with niobium oxide trichloride. The pentachloride is a lemon-yeUow crystalline soHd that melts to a red-orange Hquid and hydrolyzes readily to hydrochloric acid and niobic acid. It is soluble in concentrated hydrochloric and sulfuric acids, sulfur monochloride, and many organic solvents. 

Niobic Acid. Niobic acid, Nb20 XH2O, includes all hydrated forms of niobium pentoxide, where the degree of hydration depends on the method of preparation, age, etc. It is a white insoluble precipitate formed by acid hydrolysis of niobates that are prepared by alkaH pyrosulfate, carbonate, or hydroxide fusion base hydrolysis of niobium fluoride solutions or aqueous hydrolysis of chlorides or bromides. When it is formed in the presence of tannin, a volurninous red complex forms. Freshly precipitated niobic acid usually is coUoidal and is peptized by water washing, thus it is difficult to free from traces of electrolyte. Its properties vary with age and reactivity is noticeably diminished on standing for even a few days. It is soluble in concentrated hydrochloric and sulfuric acids but is reprecipitated on dilution and boiling and can be complexed when it is freshly made with oxaHc or tartaric acid. It is soluble in hydrofluoric acid of any concentration. 

Titanium Sulfides. The titanium sulfur system has been summarized (4). Titanium subsulftde [1203-08-6] Ti2S, forms as a gray soHd of density 4600 kg/m when titanium monosulftde [12039-07-5], TiS, is heated at 1000°C with titanium ia a sealed tube. It can also be formed by heating a mixture of the two elements at 800—1000°C. The sulfide, although soluble ia concentrated hydrochloric and sulfuric acids, is iasoluble ia alkaUes. 

Safety. Chlorosulfuric acid is a strong acid and the principal ha2ard is severe chemical bums when the acid comes into contact with body tissue. The vapor is also ha2ardous and extremely irritating to the skin, eyes, nose, and respiratory tract. Exposure limits for chlorosulfuric acid have not been estabhshed by OSHA or ACGIH. However, chlorosulfuric acid fumes react readily with moisture in the air to form hydrochloric and sulfuric acid mists, which do have estabhshed limits. The OSHA 8-h TWA limits and ACGIH TLV—TWA limits are sulfuric acid = 1 mg/m hydrochloric acid = 5 ppm or 7 mg/m (ceiling limit). 

Fair Good 135 5.6 Resistant to solutions of hydrochloric and sulfuric acids... 

The EPA defines corrosivity in terms of pH (i.e., wastes with pH <2 or >2.5) or in terms of ability to corrode steel (SAE 20) at a rate of >6.35 mm (0.250 in.) per year at a temperature of 55 C (13°F). This discussion will address corrosivity as it applies to acids and caustics. Acids are compounds that yield H ions (actually HjO ions) when dissolved in water. Common industrial acids include acetic, nitric, hydrochloric, and sulfuric acids. The terms concentrated and dilute refer to the concentrations in solution. Mixing a concentrated acid with enough water will produce a dilute acid. For example, a bottle of concentrated HCl direct from the manufacturer is approximately 12 N in HCl, while a solution of HCl used in a titration may be only 0.5 N. The latter is a dilute acid solution. 

The composition of this alloy (54% nickel, 15% molybdenum, 15% chromium, 5% tungsten and 5% iron) is less susceptible to intergranular corrosion at welds. The presence of chromium in this alloy gives it better resistance to oxidizing conditions than the nickel/molybdenum alloy, particularly for durability in wet chlorine and concentrated hypochlorite solutions, and has many applications in chlorination processes. In cases in which hydrochloric and sulfuric acid solutions contain oxidizing agents such as ferric and cupric ions, it is better to use the nickel/molybdenum/ chromium alloy than the nickel/molybdenum alloy. 

The formation of acidic deposition is largely from the combustion of fossil fuels and the smelting of sulfide ores. Minor natural sources exist such as the formation of hydrochloric and sulfuric acid from gaseous volcanic eruptions. 

The catalyst acid sites are both Bronsted and Lewis type. The catalyst can have either strong or weak Bronsted sites or, strong i)i weak Lewis sites. A Bronsted-type acid is a substance capable of donating a proton. Hydrochloric and sulfuric acids are typical Bronsted acids. A Lewis-type acid is a substance that accepts a pair of electrons. Lewis acids may not have hydrogen in them but they are still acids. Aluminum chloride is the classic example of a Lewis acid. Dissolved in water, it will react with hydroxyl, causing a drop in solution pH. 

Njkles, Proposed an incendiary compn, called "feu lorrain", consisting of hydrochloric and sulfuric acids, and a soln of phosphorus in carbon disulfide. The mixt ignites, evolving heavy reddish fumes, when brought in contact with an ammonia-cal soln... 

C. Reagent grade hydrochloric and sulfuric acid (over-poweringly potent without dilution.) Add powdered root-bark to Jar B. 

The reactions of diazoesters with hydrochloric and sulfuric acids, triphenylphosphine, and dinitrogen tetroxide resulted in aryl chloroacetates, bis(aryloxycarbonylmethyl) sulfates, triphenylphosphoranylidenehydrazones of aryl 2-oxoethanoates, and iV-oxides of diaryl l,2,5-oxadiazole-3,4-dicarboxylates <1999RJO 666>. 

Nickel was first isolated in 1751, and a relatively pure metal was prepared in 1804. In nature, nickel is found primarily as oxide and sulfide ores (USPHS 1977). It has high electrical and thermal conductivities and is resistant to corrosion at environmental temperatures between -20°C and +30°C (Chau and Kulikovsky-Cordeiro 1995). Nickel, also known as carbonyl nickel powder or C.I. No. 77775, has a CAS number of 7440-02-0. Metallic nickel is a hard, lustrous, silvery white metal with a specific gravity of 8.9, a melting point of about 1455°C, and a boiling point at about 2732°C. It is insoluble in water and ammonium hydroxide, soluble in dilute nitric acid or aqua regia, and slightly soluble in hydrochloric and sulfuric acid. Nickel has an atomic weight of 58.71. Nickel is... 

NaC103 + NaCl + H2S04 = C102 + 1/2C12 + Na2S04 + H20 Developed by W. H. Rapson at the Electric Reduction Company of Canada, now Erco Industries, United States. Erco R-3 uses chloride in sulfuric acid as the reductant Erco R-3H uses mixed hydrochloric and sulfuric acids and Erco R-5 uses chloride in hydrochloric acid. 

A majority of soil extractions of inorganic constituents are carried out to determine the metal content of a soil sample. In these cases, it is common to use add extracting solutions. Dilute hydrochloric and sulfuric acids are most commonly used. Nitric acid is an oxidizer, so undesired oxidation can occur during the extraction process using this reagent. Phosphate is a natural... 

Obtain dropper bottles containing 50% (by volume) solutions of acetic acid, hydrochloric acid, sulfuric acid, and nitric acid. Repeat steps 2 and 3 using acetic acid in place of water, testing all those for which water gave an I. Then repeat with hydrochloric acid and sulfuric acid. Repeat finally with nitric acid, but only for those for which acetic, hydrochloric, and sulfuric acids gave an I. 

Sometime around 1300 bce, an unknown alchemist described sulfuric acid. Not much is known about the early use of sulfur or sulfuric acid. In 1579 an alchemist named Andreas Libavius described the progress of alchemy. In his book he described how hydrochloric and sulfuric acids are produced and mentioned the formation of aqua regia, which is a mixture of acids that is strong enough to dissolve gold—the royal metal. 

Black monoclinic or hexagonal crystals or powder density 4.6 g/cm refractive index 1.45 hardness 1.8 Mohs decomposes at 220°C insoluble in water, ethanol and aUtabs. Ksp 8.0xl(h34j soluble in nitric acid, ammonium hydroxide and potassium cyanide solutions also soluble in hot hydrochloric and sulfuric acids. 

Colorless liquid density 1.879 g/cm at 20°C and 1.844 g/cm at 30°C refractive index 1.464 boils at 86.5°C solidifies at -49.5°C decomposes in water soluble in alcohol, ether, benzene, chloroform and carbon tetrachloride insoluble in concentrated hydrochloric and sulfuric acids. 

Actions of dilute hydrochloric and sulfuric acid on nickel are relatively slow slower than on iron. Concentrated nitric acid passivates the metal, oxidizing it and forming a protective film on its surface which prevents any further reaction. 

Nickel has typical metallic properties it can be readily rolled, drawn into wire, forged, and polished. It is also ferromagnetic and a good conductor of both heat and electricity. Nickel is positioned after hydrogen in the electrochemical series and slowly displaces hydrogen ions from dilute hydrochloric and sulfuric acids. It reacts more rapidly with nitric acid. Nickel is highly resistant to attack by strong alkalis (Hawley 1981). Black nickel oxide readily yields nickel salts... 

Good resistance to mild acids and alkalis, but may be degraded by strong acids and alkalis at high temperatures. Some are slightly yellowed by dilute hydrochloric and sulfuric acids. ... 

Petkovic, D.M. Kopecni, M.M. Mltrovic, A.A. Solvent extraction of nitric, hydrochloric and sulfuric acid and their uranyl salts with tri-n-octylphosphine oxide, Solvent Extr. Ion Exch. 10 (1992) 685-696. 

Decomposed by water with formation of hydrochloric and sulfuric acids.1... 

Hydrochloric and sulfuric acids have been employed with about equal frequency in hypophosphorous acid reductions. Recent work has shown that, in general, the reaction goes more smoothly with the diazonium chlorides,82 so that, with certain exceptions discussed below, diazotiza-tion with hydrochloric acid is advisable. The striking results obtained with the toluidines are recorded in Table I. The isomeric nitroanilines... 

The free dimeric 9-molybdophosphoric(V) and 9-tungstophosphoric(V) acids are exceptionally soluble in water (up to 85% by weight of solution), ether, absolute alcohol, and cold nitric acid. However, they are insoluble in nonpolar solvents such as chloroform, carbon disulfide, or hydrocarbons. The 2 18 arsenic acid is decomposed by hydrochloric and sulfuric acids. 

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