Aqueous Solutions of Simple Salts

On the basis of the preceding generalizations, it is possible to predict the products of electrolysis of aqueous solutions of simple salts. It is not... 

First let us note that experiment revealed long ago that not all ions prefer the bulk to the interface [8]. Gibbs adsorption equation predicts that the surface tension increases with the electrolyte concentration when the total surface excess of ions is negative. The conventional picture, that the ions prefer the bulk, is probably due to Langmuir, who noted that the increase in the surface tension of aqueous solutions of simple salts with increasing concentration can be explained by assuming a surface layer of pure solvent with a thickness of about 4 A [9]. However, because the aqueous solutions of some simple acids (such as HC1) possess surface tensions smaller than that of pure water [8], Gibbs adsorption equation indicates a positive total... 

Aqueous solutions of simple salts usually contain [Co(H20)g] + but there is evidence for the existence of equilibrium 21.82, although [Co(H20)g] + is by far the dominant species speciation in aqueous C0CI2 was discussed earlier. 

Most 5( Zn) measurements have been on aqueous solutions of simple salts and thus relate to the average of several species in rapid equilibrium. The variation of the observed shift with concentration, temperature, and deuteriation of the solvent no doubt follows changes in the equilibrium position. Using established equilibrium constants, 5( Zn) for [ZnX (OH2L] ", X = C1 and Br, n= -4 have been evaluated. The irregular sequences of values with maxima for = 2 probably reflect changes in the coordination number between complexes. The shift of Zn(N03)2... 

Bile is an aqueous solution of bile salts, inorganic salts, bile pigments, fats, cholesterol, and others. The physiology of bile secretion is not simple, as it involves the active excretion of organic solutes from the blood to the bile. Bile is collected directly from the liver cells through separate channels, without being mixed with blood. The liver cell membrane incorporates extremely fine passages that permit bile secretion. 

Both the hepta- and hexahydrate give rise to the reddish-violet Tutton s salts, M2[V(H20)6]-(804)2 (M = NH4, K, Rb, or Cs), on heatment of an aqueous solution of the salt with the appropriate alkali metal sulfate. These salts have the schonite, K2Mg(S04)2-61120, structure. They are more stable than the simple sulfate, especially in the presence of excess... 

A very simple case of a bivariant system is furnished by a solid salt in presence of an aqueous solution of this salt two independent components, the salt and the water, have two phases, the solid salt and the solution. For every temperature and pressure such a system is in equilibrium the solution is then saturated with the salt the concentration of the saturated solution depends upon the temperature to which it is brought and upon the pressure it supports but it is independent of the masses of salt and water that the S3rstem contains. Also, if to a knowledge of the temperature and pressure we join the knowledge of the total mass of the salt and water in the 83nstem, the masses of the solution and of the undissolved salt are determined. 

It is always advisable, incidentally, to measure the density of a saturated solution at the same time that the equilibrium saturation concentration is being measured, for the simple practical reason that density is the mass-volume conversion factor, and this quantity is frequently required in process calculations. Sohnel and Novotny (1985) have published an extensive compilation of concentration-density data for aqueous solutions of inorganic salts. 

Consider the simple system in which an aqueous solution of a salt containing R" and X" ions is separated from an aqueous solution of the acid HX by a... 

In the preceding sections, it is shown that simple aqueous solutions of one salt are far firom being trivial to understand. Obviously, this is all the more true, when a third component is added. 

A special case is when the adsorbable metal ion of variable valence is at the same time the redox agent. In this way, through disproportionation of Sn a catalyst modified by adsorbed Sn can be obtained (ref.13). The procedure is rather simple the catalyst (possibly oxidized on the surface) is shaken together with an aqueous solution of Sn salt. In this case the potential of the Pt catalyst is determined by the Sn Vsn " system, whose electrode potential is positive to the system, but negative to the Sn Sn system... 

The group oxidation state of +5 is too high to allow the formation of simple ionic salts even for Nb and Ta, and in lower oxidation states the higher sublimation energies of these heavier metals, coupled with their ease of oxidation, again militates against the formation of simple salts of the oxoacids. As a consequence the only simple oxoanion salts are the sulfates of vanadium in the oxidation states +3 and +2. These can be crystallized from aqueous solutions as hydrates and are both strongly... 

Several carboxylates, both simple salts and complex anions, have been prepared often as a means of precipitating the An ion from solution or, as in the case of simple oxalates, in order to prepare the dioxides by thermal decomposition. In K4[Th(C204)4].4Fl20 the anion is known to have a 10-coordinate, bicapped square antipris-matic structure (Fig. 31.8b). -diketonates are precipitated from aqueous solutions of An and the ligand by addition of alkali, and nearly all are sublimable under vacuum. [An(acac)4], (An = Th, U, Np, Pu) are apparently dimorphic but both structures are based on an 8-coordinate, distorted square antiprism. 

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