Aqueous Solutions of Alkali Halides

APPARENT MOLAL HEAT CAPACITIES OF AQUEOUS SOLUTIONS OF ALKALI HALIDES AND ALKYLAMMONIUM SALTS. 

These various silver halides are usually precipitated in batch or continuous reactors by mixing aqueous solutions of alkali halide salts and silver nitrate. One, two or more reagents may be pumped into the reactor under programmed or feedback control. Key control variables are reagent mixing and delivery, temperature, and especially silver ion activity. The latter can be electrochemically monitored by using silver or silver salt electrodes, and the relative potentials measured by such electrodes provide a means to impose feedback control... 

In our discussion of halide ion quadrupole relaxation we will follow a path of increasing complexity of the systems. First, we consider in the following subsection the relaxation rates observed for the ions at infinite dilution in water and in connection with this the theoretical treatment of relaxation due to ion-solvent interactions. In Subsection 5.1.3, experimental data for aqueous solutions of alkali halides are considered and in connection with this we outline theoretical attempts to account for effects of ion-ion interactions on the relaxation rates. Apart from alkali halide solutions few inorganic systems, mainly earth alkali halide solutions, have been studied and these are treated in Subsection 5.1.4. Hydrophobic solutes have particularly strong effects on chloride, bromide and iodide relaxation and the explanation to this is considered in Subsection 5.1.5. Long-chain hydrophobic solutes in aqueous systems form various types... 

The first to report the concentration dependence of halide ion quadrupole relaxation in aqueous solutions of strong electrolytes were Itoh and Yamagata [247]. Their and later studies have shown that whereas the change in relaxation with concentration may depend greatly on the cation present, the relaxation rate at low concentrations is independent of cation. For aqueous solutions of alkali halides, the concentration dependence of the anion quadrupole relaxation rate is in most cases weak below ca. 1 M. Consequently the relaxation rate in the... 

Aqueous solutions of alkali halides have been extensively studied by chlorine, bromine and iodine NMR. Because of the considerable linebroadening for solid alkali halides and for liquids with covalent... 

Nickolov, Z. S., and Miller, J. D. 2005. Water structure in aqueous solutions of alkali halide salts FTIR spectroscopy of the OD stretching band. J. Colloid Interface Sci. 287 572. 

Fig. 9. Logarithm of the mean ionic activity coefficient of aqueous solutions of alkali halides at 25 C. (a) LiCl, (b) NaCl,...

Figure 5 shows the influence of alkali cations [Fig. 5(a)] and halide anions [Fig. 5(b)] on the water activity coefficients in aqueous solutions of alkali halides. 

Figure 12.4 Capacity of the interface between aqueous solutions containing alkali halides and a solution of TPAs/TPB in 1,2-dichloroethane. The electrolyte concentration in both cells was 10 2 M. Alkali halides used (a) CsCl, (b) RbCl, (c) KC1, (d) NaCl, (e) LiCl. Data taken from Ref. 5.

The osmotic coefficients calculated from Eq. (9) can be brought into good agreement with solution data up to about 1M for aqueous solutions of alkali (26) and alkaline earth halides, (30) tetraalkyl ammonium halides, T3l) mixed electrolytes, where the Harned coefficients are measured, (32) and electrolyte-non electrolyte mixtures, where Setchenow coefficients are measured. 

Cadmium is rapidly oxidized by hot dilute nitric acid with the simultaneous generation of various oxides of nitrogen. Unlike the zinc ion, the cadmium ion is not markedly amphoteric, and therefore cadmium hydroxide [21041-95-2], Cd(OH)2, is virtually insoluble in alkaline media. However, the cadmium ion forms stable complexes with ammonia as well as with cyanide and halide ions. The metal is not attacked by aqueous solutions of alkali hydroxide. 

The enhanced solubilities of copper(I) halides or pseudohalides in aqueous solutions of alkali or ammonium halides are due to the formation of anionic complexes (37, 121, 134, 263) ... 

A reaction of haloforms with a base, which generates dihalocarbenes (a-elimination) and their addition to alkenes is an efficient method for the preparation of 1,1-dihalocyclopropanes, with the exception of 1,1-difluoro derivatives (Houben-Weyl, Vol.E19b, pp 1464-1466). When chlorodifluoromethane and an alkene are treated with methyllithium, potassium tcrt-butox-ide, powdered sodium hydroxide in tetraglyme or a concentrated aqueous solution of alkali metal hydroxide and a phase-transfer catalyst, the expected 1,1-difluorocyclopropanes are formed in low yields. Comparable low yields of these products result, if dichlorodi-fluoromethane and an alkene are treated with methyllithium. " The main products formed are those that result from reaction of difluorocarbene (carbenoid), and its precursor, with the base or the solvent present in the system (for examples, see refs 10-12). Therefore, the reaction of chlorodifluoromethane with base and an alkene lacks preparative value. The difficulties mentioned above are circumvented in the method using chlorodifluoromethane, oxirane (or chloromethyloxirane), with tetraalkylammonium halide as a catalyst and an alkene (Houben-eyl, Vol. 4/3, p 380 and Vol. E19b, pp 1468-1469). 

Desnoyers JE, Perron G (1972) Viscosity of aqueous solutions of alkali and tetraalkylammonium halides at 25 deg. J Solution Chem 1 199-212... 

Friedman s model fits the thermodynamic excess functions (osmotic coefficient, excess volume, and excess energy) of aqueous solutions of alkali and earth alkaline halides up to l-M ionic strength and of tetraalkylammo-nium halides up to 0.4 M. The variation of the A/y parameters with the ionic parameters is chemically meaningful and permits the estimation of thermodynamic properties of unknown systems by the combination of the parameters known from appropriate other systems. 

Recent research of structures of water solutions of alkali halides has revealed a new feature [100]. In aqueous solutions of Nal (6M) and Csl (3M), the Cs+-0 distance... 

A step mode of heat treatment of fibers under tension or in the free state in a vacuum, inert atmosphere, or in air is usually used. Table 10.3 shows how the physical-mechanical properties of fibers formed from a LC melt of a polyester based on a mixture of tere- and isophthalic acids and l,4-bis(3,5-dimethyl-4-hydroxybenzoyl)benzene [66] change as a function of the heating mode (24-h duration of each stage). The strength of the fiber increases by approximately four times as a result of the heat treatment, and this increase takes place with a simultaneous increase in the elongation at break, which is very important In many cases, thermal drawing of the fiber is less effective than its heat treatment in the free state. To reduce the duration of the heat treatment, it has been proposed that the fiber be preliminarily treated with aqueous solutions of alkali metal halides, of which potassium chloride and iodide are the most effective [67]. 

Rasaiah J C 1970 Equilibrium properties of ionic solutions the primitive model and its modification for aqueous solutions of the alkali halides at 25°C J. Chem. Phys. 52 704... 

Even in the strong alkali that favors this reaction, very little of the arsenite will be as the trianion nevertheless, there is evidence that it is this form that is responsible for the reaction (104). The insolubility of many alkyl halides in the necessarily aqueous solution of strong alkali is a limitation on this, so ways around must be found. Further, the R group of R—X should not carry a nucleophilic atom on C-4 or C-5, or else it will attack C-l with expulsion of halide and cyclization. This includes a hydroxy group, since it will be in the nucleophilic -0 form in the alkaline conditions. 

Table XXXIV.—Compressibilities of Aqueous Solutions of the Alkali Halides.

In recent years we have undertaken a systematic investigation of the volumes and heat capacities of transfer of alkali halides and tetraalkylammonium bromides from water to mixed aqueous solvents (1-6). These properties are important because, when combined with enthalpies and free energies, they can be used to calculate the temperature and pressure dependences of various equilibrium properties of electrolytes in mixed solvents. Since the properties of electrolytes in mixed aqueous solvents are closely related to the corresponding properties of the nonelectrolyte in an electrolyte solution, infor-... 

There are two principal synthetic routes to dicarboxylate complexes. One of these uses an aqueous solution of the alkali metal dicarboxylate and the corresponding metal halide,93 while the other depends upon the dicarboxylic acid reduction of higher oxidation state metals. This reductive property of oxalic acid results in its ready dissolution of iron oxides and hence a cleaning utility in nuclear power plants.94 Mention must also be made of the successful ligand exchange synthesis of molybdenum dicarboxylates, Mo(dicarboxylate)2 H2 O, from the corresponding acetate complex. Unfortunately the polymeric, amorphous and insoluble nature of these complexes has restricted the study of these systems, which may well provide examples of multiple M—M bonding in dicarboxylate coordination chemistry.95... 

In several previous papers, the possible existence of thermal anomalies was suggested on the basis of such properties as the density of water, specific heat, viscosity, dielectric constant, transverse proton spin relaxation time, index of refraction, infrared absorption, and others. Furthermore, based on other published data, we have suggested the existence of kinks in the properties of many aqueous solutions of both electrolytes and nonelectrolytes. Thus, solubility anomalies have been demonstrated repeatedly as have anomalies in such diverse properties as partial molal volumes of the alkali halides, in specific optical rotation for a number of reducing sugars, and in some kinetic data. Anomalies have also been demonstrated in a surface and interfacial properties of aqueous systems ranging from the surface tension of pure water to interfacial tensions (such as between n-hexane or n-decane and water) and in the surface tension and surface potentials of aqueous solutions. Further, anomalies have been observed in solid-water interface properties, such as the zeta potential and other interfacial parameters. 

Solutions of alkali metal and ammonium iodides in liquid iodine are good conductors of electricity, comparable to fused salts and aqueous solutions of strong acids. The liquid is therefore a polar solvent of considerable ionizing power, whereas its own electrical conductivity suggests that it is appreciably ionized, probably into I+ and I"3 (triodide). Iodine resembles water in this respect. The metal iodides and polyiodides are bases, whereas the iodine halides are acids. 

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