Nitric acid in aqueous solutions

Mahoney, L.R (1970). Evidence for the formation of hydroxyl radicals in the isomerisation of pemittous acid to nitric acid in aqueous solutions. J. Am. Chem. Soc. 92, 5262-5263. 

Table 8-9 lists processes leading to the oxidation of N02 to nitrous or nitric acid in aqueous solution. The significance of these reactions in clouds may be assessed by comparing their rates with that for the oxidation of N02 by ozone, which is the major dark reaction in the gas phase. Table 8-9 includes the latter process for comparison. 

A. Komlosi, G. Porta, and G. Stedman [Int. J. Chem. Kinet., 27, 911-917 (1995)] studied the autocatalytic oxidation of formaldehyde by nitric acid in aqueous solution. 

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) ... 

During certain substitution reactions, the carboxyl group is often replaced by the entering group. An example is fuming nitric acid, which results in the formation of trinitrophenol. Another is the bromination of saUcyhc acid in aqueous solution to yield 2,4,6-tribromophenol [25376-38-9] (eq. 6). 

Nitration by nitric acid in aqueous mineral acid solution... 

Alloxantin has been obtained by the oxidation of uric acid with nitric acid, followed by reduction with hydrogen sulfide 2 by oxidation of uric acid with potassium chlorate, followed by reduction with stannous chloride by condensation of alloxan with dialuric acid in aqueous solution and by oxidation of dialuric acid. ... 

Cerium was included in a list of 14 elements determined by Lee et al. [627] in seawater using neutron activation analysis. The metals were first precon-centraed on a mixture of Chelex 100 and glass powder. The elements were desorbed from the column by 4 M nitric acid, and aqueous solution was irradiated for 3 days and subjected to y-ray spectrometry method with a Ge(Ii) detector coupled to a 4000-channel analyser. Cerium was found to be present to the extent of 16.7 xg/l in water taken from the Kwangyang Bay (South Korea). 

Before 1970, most of the data for nitrogen oxides were obtained by continuous measurements with a colorimetric analyzer that was similar in principle to the colorimetric oxidant analyzer shown in Figure 6-8. The scrubbing agent is a mixture of -(l-naphthyl)ethylenediamine, sulfanilic acid, and acetic acid in aqueous solution. The color is produced when both nitrogen dioxide and nitrites react with this reagent to form an azo dye. The color is not affected by nitric oxide in the air sample. 

Mercury(I) nitrate is acidic in solution. Its aqueous solution hydrolyzes on standing forming a yeUow precipitate of the basic nitrate, Hg2(N03)(0H). This precipitation occurs more rapidly when diluted with water and warmed. Sufficient nitric acid in the solution suppresses hydrolysis. 

Clancy, R. M., Miyazaki, Y., and Cannon, P. J. (1990). Use of thionitrobenzoic acid to characterize the stability of nitric oxide in aqueous solutions and in porcine aortic endothelial cell suspensions. Anal. Biochem. 191, 138-143. 

Acetic acid is a weak acid in aqueous solution and nitric acid a strong add, but both behave as bases in sulfuric acid ... 

The above statement concerning the effectiveness of the nitronium ion over a wide range of conditions has not always been accepted and, until recently, some workers held that the nitronium ion was not the effective electrophile in solutions of nitric acid in aqueous acids and organic solvents. It is unnecessary now to go into these arguments since the subject has been covered in a number of recent reviews (Ridd, 1971a Hoggett et al., 1971 Stock, 1976), and the... 

As outlined above (p. 3), a reaction can be subject to microscopic diffusion control only if one of the reactive intermediates is formed from an inactive precursor in the reaction mixture. There are two sets of conditions which have provided evidence for microscopic diffusion control in nitration. One concerns solutions of nitric acid in aqueous mineral acids or organic solvents for, in most of these solutions, the stoicheiometric nitric acid is mainly present as the molecular species in equilibrium with a very small concentration of nitronium ions. A reaction between a substrate and a nitronium ion from this equilibrium concentration can, in principle, be subject to microscopic diffusion control. The other set of conditions is when the substrate is mainly present as the protonated form SH+ but when reaction occurs through a very small concentration of the neutral base S. A reaction between the neutral base and a nitronium ion can then, in principle, be subject to microscopic diffusion control even if the nitronium ions are the bulk component of the HN03/N0 equilibrium. In considering the evidence for microscopic diffusion control it is convenient to consider separately the reactions of those species involved in prototopic equilibria. 

Action of Nitric Acid on Metals.—The product of the action of nitric acid on metals varies according to the metal acted on, the concentration of the acid, and the temperature. The acid in aqueous solution is more or less + —... 

In addition, substances which are easily sulfonated, hydrolyzed, or otherwise changed, by concentrated sulfuric acid cannot be nitrated in sulfuric acid solution. In these circumstances it is necessary either to use aqueous nitric acid of suitable concentration, or to carry out the nitration with concentrated nitric acid in a solution or suspension in an organic liquid. The organic liquid must be one which is affected as little as possible by nitric acid under the conditions prevailing in the process (for example, glacial acetic acid, nitrobenzene, or o-dichlorobenzene). 

HNO3 Nitric acid 102° "AVi, 114° Strong acid in aqueous solution concentrated aqueous solutions are strong oxidizing agents... 

Where Ka is the acid dissociation constant. (Note that the definition of Ka is based on the Bronsted definition.) Values of Ka can vary tremendously (IQis to 10-60). after all anything with at least one proton can be considered an acid under some circumstances with this definition. The common definition of a strong acid is an acid which dissociates completely in a 1 M solution. The common strong acids in aqueous solution, such as sulphuric, nitric and hydrochloric acids have Ka values (for the first dissociation in the case of sulfuric) of 10 to 10. Thus they all dissociate completely (first dissociation only for sulphuric) in aqueous solution, though they wiU have different strengths in some other solvents. Most common organic acids are weak in aqueous solution, having Ka values of lO-s to Note that... 

According to Arrhenius, an acid in aqueous solution ionizes to form hydronium ions, HsO", as shown here for nitric acid, HNO3. 

Compare the behaviour of nitric acid in aqueous and sulfuric acid solutions, giving examples from both inorganic and organic chemistries of the uses of HNO3 in these two media. 

Solubility OF Boric Acid in Aqueous Solutions of Hydrochloric, Sulphuric, and Nitric Acids at 26°. 

The typical electrodeposition process observed with nickel derivatives was first investigated by Milczarek using a Ni(II) tetrakis(3-methoxy-4-hydroxyphenyl) porphyrin as a monomer. The resulting conductive film was used for the electro-catalytic oxidation of methanol and other simple alcohols , nitric oxide, formaldehyde , or ascorbic acid and NADH. Later, [Ni(II)-69], [Ni(II)-70] and [Ni(II)-71] were shown to provide a large benefit in the electrochemical determination of nitric oxide in aqueous solution or for the electrocatalytic... 

Fig. 3. Dependence of distribution coefficient of Pu(IV) into TBP on concentration of nitric acid in aqueous phase (for 281 solutions not containing uranyl nitrate). Curve 1-20, curve 2-30, curve 3-50°, and curve 4-70. ...

The distribution of nitric acid between aqueous solution and 100 TBP is demonstrated in figure The, distri-... 

In aqueous solution arsenic(lll) oxide is a reducing agent being oxidised to arsenate(V) by halogens, chlorate(I), nitric acid and even iron(III) chloride. 

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