Solubility hydrated ions

Many ionic halides dissolve in water to give hydrated ions. The solubility of a given halide depends on several factors, and generalisations are difficult. Ionic fluorides, however, often differ from other halides in solubility. For example, calcium fluoride is insoluble but the other halides of calcium are highly soluble silver fluoride. AgF, is very soluble but the other silver halides are insoluble. 

Water-soluble pAM neutral polymer interacts with ions of the solution through the complex formation between amide groups and hydrated ions. 

SiOj-xHsO. This hydrated oxide docs react with hydroxide ion to form soluble silicate ions ... 

In such a case, chemical interaction with the solution can take place. This is likely to be primarily the protonation (hydration) reaction leading to formation of some soluble complex ions which diffuse toward the bulk of the solution. Hence, this produces a mechanism for dissolving and thinning the oxide layer, and the rate of this process should be some function of the hydrogen ion... 

Most primary and secondary minerals found in soil systems are barely soluble in the soil solution. The amount of mass from the bulk phase to hydrated ions in soil solution is negligible compared to the total mass of the solid phase. In arid and semi-arid soils, concentrations of most trace metals in soil solution may be controlled by their carbonates and to some extent by their hydroxides. Other than carbonates, trace elements in arid and semi-arid soils may also occur as sulfate, phosphate or siliceous compounds, or as a minor component adsorbed on the surface of various solid phase components. The solubility of carbonates, sulfates and other common minerals of trace elements in arid and semi-arid soils will be discussed in Chapter 5. Badawy et al. (2002) reported that in near neutral and alkaline soils representative of alluvial, desertic and calcareous soils of Egypt, the measured Pb2+ activities were undersaturated with regard to the solubility of... 

In Investigation 9-A, you will collect solubility data and use these data to determine a Ksp for calcium hydroxide, Ca(OH)2. When you calculate Ksp, you assume that the dissolved ionic compound exists as independent hydrated ions that do not affect one another. This assumption simplifies the investigation, but it is not entirely accurate. Ions do interfere with one another. As a result, the value of Ksp that you calculate will be just an approximation. iCp values that are calculated from data obtained from experiments such as Investgation 9-A are generally higher than the actual values. 

In acidic solution the + 2 and + 3 oxidation states are simple hydrated ions, the +4 and + 5 states being oxocations. In alkaline solution the + 2 and +3 states form neutral insoluble oxides (the lattice energies of the oxides giving even more stability than any soluble form in these cases), and the +4 and +5 states exist as oxyanions (dimeric in the +4 case). 

X-ray and neutron diffraction methods and EXAFS spectroscopy are very useful in getting structural information of solvated ions. These methods, combined with molecular dynamics and Monte Carlo simulations, have been used extensively to study the structures of hydrated ions in water. Detailed results can be found in the review by Ohtaki and Radnai [17]. The structural study of solvated ions in lion-aqueous solvents has not been as extensive, partly because the low solubility of electrolytes in 11011-aqueous solvents limits the use of X-ray and neutron diffraction methods that need electrolyte of -1 M. However, this situation has been improved by EXAFS (applicable at -0.1 M), at least for ions of the elements with large atomic numbers, and the amount of data on ion-coordinating atom distances and solvation numbers for ions in non-aqueous solvents are growing [15 a, 18]. For example, according to the X-ray diffraction method, the lithium ion in for-mamide (FA) has, on average, 5.4 FA molecules as nearest neighbors with an... 

Let s consider the solubility equilibrium in a saturated solution of calcium fluoride in contact with an excess of solid calcium fluoride. Like most sparingly soluble ionic solutes, calcium fluoride is a strong electrolyte in water and exists in the aqueous phase as dissociated hydrated ions, Ca2+(aq) and F (aq). At equilibrium, the ion concentrations remain constant because the rate at which solid CaF2 dissolves to give Ca2+(aq) and F aq) exactly equals the rate at which the ions crystallize to form solid CaF2 ... 

It has been proposed that there may be a close link between the amount of an element available to living matter and the fraction of the total content which is labile (with the lability value being loosely defined as the total, accessible, hydrated ion level). Either the whole or part of the analytical result may be derived from dissociation of labile complex ions or dissolution of moderately soluble compounds. If one or both of these two processes proceed at a relatively slow rate, the magnitude of the lability value becomes time dependent . Conversely, if a complex exchanges ligands fairly rapidly, the amount present in... 

Salt formation usually improves the water solubility of acidic and basic drugs because the salts of these drugs dissociate in water to produce hydrated ions ... 

From the free-energy considerations, one can calculate the reversible potentials for a metal that is in equilibrium with its simple hydrated ions or with its soluble product of hydrolysis or with its insoluble oxide. Under the given conditions, the... 

Cu+ makes the hydrated ion the more stable in aqueous solution. Thus soluble copper(I) compounds always disproportionate ... 

The sodium potassium tartrate initially forms the soluble blue copper(II) tartrate complex witli the copper sulfate the color of this complex is a deeper blue than that of the hydrated ion. At the temperature of the experiment reduction to the beautiful golden orange CuzO occurs, and at the same time oxygen and (rather less) CO2 are formed in the redox proce.ss these are responsible lor the foaming of the solution. This reversible color reaction can be repeated several times when further hydrogen peroxide is added. The pH of the system increases from 5 to about 9. ... 

When the two ionic transfers are simultaneously in equilibrium, the concentration of hydrated ions corresponds to the solubility product of the ionic solid in the solution. 

The key point for atmospheric steel corrosion is to make an initial corrosion product of soluble ferrous ions air-oxidized as soon as possible into an insoluble ferric hydroxide aggregate, which eventually turns into anticorrosive mst. The air-oxidation of hydrated ferrous ions is fast in neutral water but slow in acidic water. Once corrosion-produced ferrous ions are oxidized into gel-like... 

Extraction of ions. Methods to reduce salt loadings were, in the beginning, more or less restricted to the application of wet compress materials, e.g. cellulose pulp, to the surface of the paint layer. The enhanced humidity leads to hydration and enhanced solubility of ions that are transferred to the surface, and migrate into the pulp material by evaporation of water from the compresses. Repeated applications are necessary and the quantity of ions extracted has to be measured to decide to what extent the extractions should be done. Obviously these extraction techniques can only be successful, if it can be assured that there will be no further transport of ions into the painting, possibly enhanced by the method of attracting the salts into the compress. Hence the... 

Both the lack of freezing and the inability of ions to enter the pores containing motionally restricted water can be explained by the existence of fragmented clusters such as monomors, dimers etc. Thus, the presence of these fragmented clusters prevent the necessary aggregation and co-operative expansion needed for an ice-like structure to exist, while at the same time they are less able to hydrate ions resulting in low solubilities and consequently low rejections in the desalination sense (1,2 ). This could be the microscopic mechanistic basis for the solution-diffusion model so... 

In this equation the calcium sulfate is represented by separate hydrated ions because calcium sulfate is quite water soluble and dissolves in rainwater. Thus, in areas bathed by rainwater, the marble slowly dissolves away. 

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