Nitrate ion in aqueous solution

Wagner I, Strehlow H, Busse G. Flash photolysis of nitrate ions in aqueous solutions. Z Phys Chem (NF) 1980 123 1-33. 

Table 1 Main reactions induced on aromatic compounds by excitation of nitrate ions in aqueous solution...

The heat of mixing in NMA from the six possible mixing experiments involving NaBr, Nal, Pr4NBr and Pr4NI (taken in pairs) have been reported by Falcone and Wood183 They have concluded that interactions occur between the iodide ions and the tetra-n-propylammonium ions in NMA solution which are comparable to the interactions between potassium ions and nitrate ions in aqueous solution. 

It is likely that as further anhydrous nitrates are prepared, further examples of such behavior will be found. Certain ruthenium nitrates also give nitrite on hydrolysis (28). All metal nitrates which by their covalent bonding can release NO2 radicals during reaction need not necessarily give nitrite on hydrolysis the latter is a complicated process which involves the coordination chemistry of the metal. For example, copper nitrate gives only nitrate ions in aqueous solution, but its reactions with ethers are at present interpreted on a free-radical basis. 

Many organic and inorganic compounds are oxidized by concentrated HNO3, although nitrate ion in aqueous solution is usually a very slow oxidizing agent (see above). Aqua regia contains free CI2 and ONCl and attacks Au (reaction 14.116) and Pt with the formation of chloro complexes. 

There is considerable evidence for the association of Bi3+ ion with nitrate ions in aqueous solution. The nitrate ions appear to be mainly bidentate, and all members of the set Bi(N03) (H20)3 +. .. Bi(N03)4 appear to occur.70 From acid solution various hydrated crystalline salts such as Bi(N03)3 5H20, Bi2(S04)3 and double nitrates of the type M3[Bi(N03)6]2,24H20 can be obtained. Treatment of Bi203 with nitric acid gives bismuthyl salts such as BiO(N03) and Bi202(0H)(N03). Similar bismuthyl salts are precipitated on dilution of strongly acid solutions of various bismuth compounds. Bismuthyl salts are generally insoluble in water. 

Conductometric methods have been used to follow the reactions of the transient species formed by flash photolysis (X 200 nm) of nitrate ions in aqueous solution. The initial excited state produced was shown to decay by two routes either to give HOONO or to give a lower energy excited state. Other reactions observed, and also those described previously by other workers, are summarized in Figure 1. A study of the photolysis of HN3 induced by 290 nm dye-laser pulses has been reported. The isomerization of NjFj in the presence of fluorine and oxygen has been initiated photochemically. ... 

Figure 1 Kinetic pathways in the photolysis of nitrate ions in aqueous solutions (Reproduced by permission from Z. Phys. Chem., 1980, 123, 1).

The most traditional approach for the electrodeposition of metal oxides and hydroxides is based on the cathodic electrogeneration of base [6]. Depending upon the deposition potential, choice of the anion and the pH of the solution, various reactions take place at the cathode, such as the reduction of nitrate ions in aqueous solutions. These reduction reactions cause a local pH increase in vicinity of the cathode either by the consumption of protons or by the generation of hydroxide ions as in the case of nitrate reduction, which subsequently leads to the precipitation of metal hydroxides. The best known application of this technique is the synthesis of nickel hydroxide by the electroreduction of aqueous nickel nitrate solutions. Depending on the metal and deposition conditions, this cathodic technique often yields hydroxides rather than oxides, making a post-deposition calcination for the transformation of the hydroxide to the oxide necessary. Unfortunately, the deposited amorphous hydroxides are often metastable. Other cathodic electrodeposition methods involve the direct reduction of the oxidation state of the metal cation and deposition of the oxide onto the electrode [9]. 

Figure 1 illustrates the complexity of the Cr(III) ion in aqueous solutions. The relative strength of anion displacement of H2O for a select group of species follows the order perchlorate < nitrate < chloride < sulfate < formate < acetate < glycolate < tartrate < citrate < oxalate (12). It is also possible for any anion of this series to displace the anion before it, ie, citrate can displace a coordinated tartrate or sulfate anion. These displacement reactions are kineticaHy slow, however, and several intermediate and combination species are possible before equiUbrium is obtained. 

We have seen in Experiment 8 that silver chloride has low solubility in water. This is also true for silver bromide and silver iodide. In fact, these low solubilities provide a sensitive test for the presence of chloride ions, bromide ions, and iodide ions in aqueous solutions. If silver nitrate... 

We could not find any study of Bi(III) ions in aqueous solutions except that Wang et al. [132] obtained nanorods of bismuth sulphide by sonicating an aqueous solution of bismuth nitrate and sodium thiosulphate in the presence of complexing agents such as ethylenediamine tetraacetic acid, triethanolamine and sodium tarta-rate. Similar results were found when thioacetamide was used in place of sodium thiosulphate as a source of sulfur. However, the results improved with higher yield... 

Ammonium nitrate dissociates in aqueous solution to NHj and NO3 ions. The former may be measured by ammonium ion-selective electrode and the latter by nitrate ion-selective electrode. The solid may be heated carefully at low temperature (around 90°C) and the evolved ammonia and nitric acid vapors are absorbed in water and measured by selective ion electrodes, respectively. 

Elemental composition Cu 64.18%, Cl 35.82%. Copper(I) chloride is dissolved in nitric acid, diluted appropriately and analyzed for copper by AA or ICP techniques or determined nondestructively by X-ray techniques (see Copper). For chloride analysis, a small amount of powdered material is dissolved in water and the aqueous solution titrated against a standard solution of silver nitrate using potassium chromate indicator. Alternatively, chloride ion in aqueous solution may be analyzed by ion chromatography or chloride ion-selective electrode. Although the compound is only sparingly soluble in water, detection limits in these analyses are in low ppm levels, and, therefore, dissolving 100 mg in a liter of water should be adequate to carry out aU analyses. 

ARU] Aruga, R., Thermodynamics of ion pairing of nitrate and chlorate with metal ions in aqueous solution, J. Chem. Soc. Dalton Trans., (1975), 2534-2538. Cited on pages 202, 372. 

Nitration in Aqueous Nitric Acid. A similar pattern of behavior is found in aqueous nitric acid. Highly reactive substrates show zero-order kinetics, and less reactive compounds show first-order kinetics in about 40 mole per cent aqueous nitric acid. The rate of nitration of the reactive compounds is the same as the rate of exchange of between HNG and HaG . This constitutes the most convincing evidence for nitration by nitryl ion in aqueous solution. The rate-determining step in each reaction is the formation of the nitryl ion. The exchange of oxygen between nitric acid and water occurs in the following steps ... 

The UV-Vis aqueous phase absorption spectra of dioxouranium(VI) solution before and after the extraction are depicted in Fig. 6.2. The initial dioxouranium(Vl) solutions show characteristic absorption bands similar to those described in the literature for dioxouranium(Vl) ions in aqueous solutions (Wang et al. 2009). As it can be seen, the shifts in the absorption peaks with nitric acid concentration are negligible, i.e. the peak at 414 nm with 0.01 M nitric acid has shifted to 415 nm and to 416 nm as the nitric acid concentration is increased to 1 M and 3 M, respectively. This slight shift is probably due to the formation of dioxouranium(VI) nitrate complexes in the acid solution (Wang et al. 2009). 

In Table 9.3 the intersection of the lead(II)-ion line and the bromide-ion column shows that lead(II) bromide is insoluble lead(II) bromide forms a solid precipitate, PbBr2(s). The intersection of the sodium-ion line and the nitrate-ion column shows that sodium nitrate is soluble in water sodium nitrate remains in aqueous solution, NaNOjCaq). Both conclusions can also be reached from the solubility guidelines Lead(II) bromide is one of the three insoluble bromides, and all sodium and nitrate compounds are soluble. 

The precipitate forms as a result of the very strong attractive forces between the Pb + cations and the 1 anions. The other product is the water-soluble salt potassium nitrate, KNO3. The potassium and nitrate ions do not take part in the reaction. They remain in solution as aqueous ions and therefore are often referred to as spectator ions. The guidelines that help identify which ions form a precipitate and which ions remain in solution are developed in a later chapter on ions in aqueous solutions. 

The interaction between and NOj" ions in aqueous solutions has been studied by several techniques during the past 20 years. A literature survey up to the early 1970s is presented in Gmdin (1974). The main question that has been debated concerns the nature of the complexation is it inner or outer sphere From thermodynamic considerations, Choppin (1971) arrived at a predominantly outer-sphere model see also Choppin and Bertha, 1973. However, in a recent study of fluorescence spectra and lifetimes, Biinzli and Yersin (1979) suggested inner-sphere complexation for europium nitrate, in contrast to the corresponding perchlorate system, see fig. 70. After studying the effect of various ligands on the " Fq transition. 

Chemical species that induce SCC in carbon and low-alloy carbon steels, even at low concentrations include hydroxides, gaseous hydrogen, gaseous chlorine, hydrogen chloride, hydrogen bromide, aqueous nitrate solutions, hydrogen sulfide gas, MnS and MnSe inclusions in the alloy. As, Sb, and Bi ions in aqueous solution, carbon monoxide-carbon dioxide-water gas mixtures. Many of these chemical systems will crack steel at room temperatures. 

The actinide ions in aqueous solution resemble the tripositive lanthanide ions in their precipitation reactions, allowing for differences in the redox properties of early members of the actinide series. The chloride, bromide, nitrate, bromate, and perchlorate anions form water-soluble salts, which can be isolated as hydrated solids by evaporation. The acetates, iodates, and iodides are somewhat less soluble in water. The sulfates are sparingly soluble in hot solutions, somewhat more soluble in the cold. Insoluble precipitates are formed with hydroxide, fluoride, carbonate, oxalate, and phosphate anions. Precipitates formed from aqueous solution are usually hydrated, and the preparation of anhydrous salts from the hydrates without formation of hydrolyzed species can only be accomplished with difficulty. The actinide(iv) ions resemble Ce(iv) in forming fluorides and oxalates insoluble even in acid solution. The nitrates, sulfates, perchlorates, and sulfides are all water-soluble. The iv state actinide ions form insoluble iodates and arsenates even in rather strong acid solution. The... 

Pt-electrodes coated with an electrochemically prepared 3-methylPT layer have enhanced anodic current response in cyclic voltammetry in nitrate and perchlorate aqueous solutions compared to the response in other salt solutions because of the oxidizing character of the two mentioned ions therefore 3-methylPT has been claimed as a material for sensors for oxidizing ions in aqueous solutions [203, 204]. 

This is an acid-base reaction, in which the base is the oxide ion (p. 89) the acidic oxide SiOj displaces the weaker acidic oxide CO2 in the fused mixture. But in aqueous solution, where the 0 ion cannot function as a strong basefp. 89),carbon dioxide displaces silica, which, therefore, precipitates when the gas is passed through the aqueous silicate solution. In a fused mixture of silica and a nitrate or phosphate, the silica again displaces the weaker acidic oxides N2O5 and P4OJ0 ... 

Unfortunately, addition of copper(II)nitrate to a solution of 4.42 in water did not result in the formation of a significant amount of complex, judging from the unchanged UV-vis absorption spectrum. Also after addition of Yb(OTf)3 or Eu(N03)3 no indications for coordination were observed. Apparently, formation of a six-membered chelate ring containing an amine and a ketone functionality is not feasible for these metal ions. Note that 4.13 features a similar arrangement and in aqueous solutions, likewise, does not coordinate significantly to all the Lewis acids that have been... 

The operation of the nitronium ion in these media was later proved conclusively. "- The rates of nitration of 2-phenylethanesulphonate anion ([Aromatic] < c. 0-5 mol l i), toluene-(U-sulphonate anion, p-nitrophenol, A(-methyl-2,4-dinitroaniline and A(-methyl-iV,2,4-trinitro-aniline in aqueous solutions of nitric acid depend on the first power of the concentration of the aromatic. The dependence on acidity of the rate of 0-exchange between nitric acid and water was measured, " and formal first-order rate constants for oxygen exchange were defined by dividing the rates of exchange by the concentration of water. Comparison of these constants with the corresponding results for the reactions of the aromatic compounds yielded the scale of relative reactivities sho-wn in table 2.1. 

NITRATION IN AQUEOUS SOLUTIONS OF MINERAL ACIDS 2.4.1 The state of nitric acid in aqueous sulphuric acid Nitric acid is completely converted into nitronium ions in concentrated sulphuric acid ( 2.3.1) ... 

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