Nitric acid, electrical conductivity

Solutions of nitric acid in 100% sulphuric acid have a high electrical conductivity. If nitric acid is converted into a cation in these solutions, then the migration of nitric acid to the cathode should be observed in electrolysis. This has been demonstrated to occur in oleum and, less conclusively, in concentrated acid, observations consistent with the formation of the nitronium ion, or the mono- or di-protonated forms of nitric acid. Conductimetric measurements confirm the quantitative conversion of nitric acid into nitronium ion in sulphuric acid. ... 

THE STATE OF NITRIC ACID IN INERT ORGANIC SOLVENTS The absence of ions in mixtures of acetic acid and nitric acid is shown by their poor electrical conductivity and the Raman spectra of solutions in acetic acid, nitromethane, and chloroform show only the absorptions of the solvent and molecular nitric acid the bands corresponding to the nitronium and nitrate ions cannot be detected. -... 

In an excess of nitric acid, nitrous acid exists essentially as dinitrogen tetroxide which, in anhydrous nitric acid, is almost completely ionised. This is shown by measurements of electrical conductivity, and Raman and infra-red spectroscopy identify the ionic species... 

These equilibria effect a rapid exchange of N atoms between the various species and only a single N nmr signal is seen at the weighted average position of HNO3, [NOa]" " and [N03]. They also account for the high electrical conductivity of the pure (stoichiometric) liquid (Table 11.13), and are an important factor in the chemical reactions of nitric acid and its non-aqueous solutions see below. 

NOj ions/ Addition of water to nitric acid at first diminishes its electrical conductivity by repressing the autoprotolysis reactions mentioned above. For example, at -10° the conductivity decrea.ses from 3.67 x 10 ohm cm to a minimum of 1.08 x 10" ohm" cm at 1.75 molal H2O (82.8% NjOs) before rising again due to the increasing formation of the hydroxonium ion according to the acid-base equilibrium... 

Graphite bisulfates are formed by heating graphite with a mixture of sulfuric and nitric acids. In the reaction, the graphite planes are partially oxidized. There is approximately one positive charge for every 24 carbon atoms, and the HS04 anions are distributed between the planes, (a) What effect is this oxidation likely to have on the electrical conductivity (b) What effect would you expect it to have on the x-ray diffraction pattern observed for this material Refer to Major Technique 3 on x-ray diffraction, which follows this set of exercises. 

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... 

Mercury forms alloys, called amalgams, with other metals such as gold, silver, zinc, and cadmium. It is not soluble in water, but will dissolve in nitric acid. It has a high electric conductivity, making it useful in the electronics industry. However, unlike most other metals, it is a poor conductor of heat. Because of its high surface tension, it does not wet the surfaces that it touches. This characteristic also accounts for its breakup into tiny droplets when poured over a surface. If spilled, it should not be collected with bare hands, but with a thin piece of cardboard to scoop it up. 

While we have not yet carried out detailed kinetic measurements on the rate of photocorrosion, our impression is that the process is relatively insensitive to the specific composition of the strontium titanate. Trace element compositions, obtained by spark-source mass spectrometry, are presented in Table I for the four boules of n-SrTi03 from which electrodes have been cut. Photocorrosion has been observed in samples from all four boules. In all cases, the electrodes were cut to a thickness of 1-2 mm using a diamond saw, reduced under H2 at 800-1000 C for up to 16 hours, polished with a diamond paste cloth, and etched with either hot concentrated nitric acid or hot aqua regia. Ohmic contacts were then made with gallium-indium eutectic alloy, and a wire was attached using electrically conductive silver epoxy prior to mounting the electrode on a Pyrex support tube with either epoxy cement or heat-shrinkable Teflon tubing. 

The sp. gr. of mixtures of sulphuric and nitric acids was measured by E. Roberts, and P. Pascal and M. Gamier—for some of A. V. Saposchnikoff s results, vide infra, electrical conductivity. According to A. Marshall the following represents the sp. gr. of the mixtures at 18°/18° when the sp. gr. of the sulphuric acid is 1-8437, and of nitric acid, 1-5009 ... 

According to F. Kohlrausch and 0. Grotrian, the electrical conductivity of nitric acid increases as the cone, increases up to 30-33 per cent. HN03 and thereafter decreases. Measurements were also made by H. Crompton, E. Bouty,... 

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