Perchloric acid density

Jacquet, Medard and Sartorius [63, 64] investigated the process of mixing 62.7% perchloric acid (density 1.59) with 100% acetic anhydride. They found that no explosion occurred when vigorous mixing was applied. This was independent of the order of mixing but addition of the acid to the anhydride was suggested to be the less dangerous procedure. 

The metal has a silvery appearance and takes on a yellow tarnish when slightly oxidized. It is chemically reactive. A relatively large piece of plutonium is warm to the touch because of the energy given off in alpha decay. Larger pieces will produce enough heat to boil water. The metal readily dissolves in concentrated hydrochloric acid, hydroiodic acid, or perchloric acid. The metal exhibits six allotropic modifications having various crystalline structures. The densities of these vary from 16.00 to 19.86 g/cms. 

Chlorine heptoxide is more stable than either chlorine monoxide or chlorine dioxide however, the CX C) detonates when heated or subjected to shock. It melts at —91.5°C, bods at 80°C, has a molecular weight of 182.914, a heat of vapori2ation of 34.7 kj/mol (8.29 kcal/mol), and, at 0°C, a vapor pressure of 3.2 kPa (23.7 mm Hg) and a density of 1.86 g/mL (14,15). The infrared spectmm is consistent with the stmcture O CIOCIO (16). Cl O decomposes to chlorine and oxygen at low (0.2—10.7 kPa (1.5—80 mm Hg)) pressures and in a temperature range of 100—120°C (17). It is soluble in ben2ene, slowly attacking the solvent with water to form perchloric acid it also reacts with iodine to form iodine pentoxide and explodes on contact with a flame or by percussion. Reaction with olefins yields the impact-sensitive alkyl perchlorates (18). 

Table 21.16 Exchange current densities for several noble metals and a platinum-rhodium alloy in the reduction of oxygen from perchloric acid solution ...

At more positive potentials, processes occur that depend on the composition of the electrolyte, such as the formation of H2S2Og and HS05 in sulphuric acid solutions, while the CIO radical is formed in perchloric acid solutions, decomposing to form C102 and 02. The formation of ozone has been observed at high current densities in solutions of rather concentrated acids. 

The oxygen content of NP is higher than that of most other crystaUine materials. Thus, its chemical potential as an oxidizer is high when combined with a fuel component. Since its theoretical density is 2220 kg m" and its heat of formation is a positive value, r-33.6 kj moT, NP is an ideal material to serve as an oxidizer. However, N P is extremely hygroscopic and its hydrolysis forms nitric acid and perchloric acid according to ... 

The effect of fluoride ions on the electrochemical behaviour of a metal zirconium electrode was studied by Pihlar and Cencic in order to develop a sensor for the determination of zirconium ion. Because elemental zirconium is always covered by an oxide layer, the anodic characteristics of a Zr/Zr02 electrode are closely related to the composition of the electrolyte in contact with it. These authors found the fluoride concentration and anodic current density to be proportional in hydrochloric and perchloric acid solutions only. In other electrolytes, the fluoride ion-induced dissolution of elemental zirconium led to an increase in the ZrOj film thickness and hindered mass transport of fluoride through the oxide layer as a result. The... 

Ozone may be produced by electrolysis of chdled dilute sulfuric acid (e g. 2.5N H2SO4) or perchloric acid at high current density (higher than that required to produce oxygen alone). A mixture of oxygen and ozone evolve at the anode. 

Gray metallic soM cubic structure very hard, hardness > 8.0 Mohs density 6.73 g/cm3 melts at 3,532°C insoluble in water slightly soluble in concentrated sulfuric acid soluble in hydrofluoric acid and oxidizing acids, such as nitric and perchloric acids attacked by oxidizers... 

Structural changes of silver terrace domains during Ag electrodissolution in aqueous perchloric acid at constant anodic current density were followed by in situ STM sequential imaging [388]. 

Figure 6.20. Experimental linear sweep voltammogram of carbon-supported high surface area nanoparticle electrocatalyst in oxygen-saturated perchloric acid electrolyte (room temperature). Solid curve pure Pt dashed curve Pt50Co50 alloy electrocatalyst. Inset a blow up of the kinetically controlled ORR regime. Inset b comparison of the specific (Pt surface area normalized) current density of the Pt and the Pt alloy catalyst for ORR at 0.9 V.

The density of 70.5 wt% aqueous perchloric acid is 1.67 g/mL. Recall that grams refers to grams of solution (= g HC104 + g HzO). 

Figure 4.29 Scattering length density profiles for an [Os(bpy)2(PVP)ioCl]Cl film in (a) perchloric acid, and (b) p-toluene sulfonic acid at different pff levels. From R.W. Wilson, R. Cubitt, A. Glidle, A.R. ffillman, P.M. Saville and J.G. Vos, A neutron reflectivity study of [Os(bpy)2(PVP)ioCl]+ polymer film modified electrodes effect of pff and counterion, /. Electrochem. Soc., 145,1454-1461 (1998). Reproduced by permission of The Electrochemical Society, Inc...

Teflon FEP (fluorinated ethylene propylene). This material is translucent and flexible, and it feels heavy because of its high density. It resists all known chemicals except molten alkali metals, elemental fluorine, and fluorine precursors at elevated temperatures. It should not be used with concentrated perchloric acid. FEP withstands temperatures from -270°C to + 205°C and may be sterilized repeatedly by all known chemical and thermal methods. It can even be boiled in nitric acid. 

To evaluate this process, salicylic acid has been used as a model of organic pollutant. In all the experimental tests, a constant current density was applied (15.8 mA cm-2). The organic pollutant was used at two different levels of concentrations (3.6 and 7.2 mmol dm-3), in order to include the mediated oxidation during the final or entire treatment time. Sulfuric or perchloric acids were used at the same concentration (l mol dm-3) to assure the same pH value in the wastewater. The use of perchloric acid impeded mediated oxidation while maintaining the same conductivity and acid condition in the wastewater as in the case of wastewater containing sulfuric acid. 

Fig. 9.3 COD/CODin vs. treatment time, with a low initial salicylic acid and sulfuric or perchloric acid. Salicylic acid concentration 3.6 mmol dm-3, sulfuric acid or perchloric acid concentration 1 mol dm-3, temperature 70°C, applied current density 15.8 mA cm-2...

Perchloric acid (concentrated). The concentrated perchloric acid solution is a clear, colourless liquid with a density of 1-54 gem-3 and contains 60% (w/w) HC104 (or 0-92 g HC104 per ml). It is approximately 9-2 molar. 

T. Taketa. J. Sci. Hiroshima Univ., Ser. A, 19, 193-202 (1955) (in English). Density, surface tension, Raman evidence of polymerization of perchloric acid. 

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