Ionic Compounds in Aqueous Solutions

Equation 14 gives a maximum exchange rate due to bulk diffusion of ions in the solution in the absence of any additional source of activation energy. 

If the crystal is charged in the solution, the rates of removal, v, and deposition,, of each ion may be given by 

For a freely dissolving crystal MX in an undersaturated solution for which, at the isoelectric point, the rates of exchange for and X are (v,i - Vg,) and (v - v ), the net removal rates must be equal, i.e., 

In this equation, the suffixes 1 and 2 denote cations and anions, respectively. 

In the case of dissolution in pure solvents, i.e., when the concentration of both ions in the solution is zero, such that v = 0, from Eq. 17 one gets 

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Which of the following best represents a molecular-scale view of an ionic compound in aqueous solution Explain. 

Using Molecular Scenes to Depict an Ionic Compound in Aqueous Solution... 

Chapter 4 presents a new molecular-scene sample problem on depicting an ionic compound in aqueous solution. 

Wet chemical precipitation is a popular method, used widely for synthesizing nano-HA at low temperature. A precipitation reaction is a common type of chemical reaction in solution chemistry where two or more solutions are combined to produce an insoluble solid product, a precipitate. Typically, these types of reaction involve ionic compounds in aqueous solution. To initiate precipitation, the solu-... 

The most numerous cases of homogeneous catalysis are by certain ions or metal coordination compounds in aqueous solution and in biochemistry, where enzymes function catalyticaUy. Many ionic effects are known. The hydronium ion and the hydroxyl ion OH" cat-... 

Write the net ionic equation for the formation of each of the following insoluble compounds in aqueous solution ... 

Surfactants are surface-active compounds, which are used in industrial processes as well as in trade and household products. They have one of the highest production rates of all organic chemicals. Commercial mixtures of surfactants consist of several tens to hundreds of homologues, oligomers and isomers of anionic, non-ionic, cationic and amphoteric compounds. Therefore, their identification and quantification in the environment is complicated and cumbersome. Detection, identification and quantification of these compounds in aqueous solutions, even in the form of matrix-free standards, still poses the analyst considerable problems. 

Diamonium pentachlorooxomolybdate(V) is an emerald green solid, stable in air. It is hygroscopic and should be stored in a stoppered vial in a desiccator. In concentrated HC1, a solution (> 10M) of the compound is green. In dilute HC1 (< 10M) the solution is greenish-brown or borwnish-red. The compound undergoes extensive ionic dissociation in aqueous solution. It is insoluble in benzene, chloroform, dichloromethane, and carbon tetrachloride. It is soluble (with decomposition) in ethanol, methanol, acetone, and pyridine a white solid of ammonium chloride precipitates from all these solutions immediately. The compound dissolves in dimethyl sulfoxide without decomposition. The electronic spectrum in 10 M HC1 contains the following absorptions 14,100(emax = 11), 22,500(emax = 10), 28,200(emax = 570),... 

Fast atom bombardment mass spectrometry (FABMS) has become an important addition to the ionization techniques available to the analytical chemist in recent years. It has been particularly useful in a number of diverse applications which include molecular weight determinations at high mass, peptide and oligosaccharide sequencing, structural analysis of organic compounds, determination of salts and metal complexes, and the analysis of ionic species in aqueous solutions. This paper will focus on some aspects of the quantitative measurement of ionic species in solution. The reader is referred to a more comprehensive review for more details of some of the examples given here as well as other applications (1). 

The chemical reaction for mineral dissolution in Eq. 3.1 (the forward reaction) represents the stoichiometric decomposition of a binary solid compound into aqueous ionic species. It is an overall reaction based on a chemical formula for the solid phase and the hypothesis that free ionic species in aqueous solution will be created in proportion to their stoichiometry in the solid for at least some time... 

Whereas Al alkyls and alkyl halides are completely hydrolyzed in water, dialkyl compounds of Ga, In, and Tl give well-characterized compounds in aqueous solution. Thallium gives very stable ionic derivatives of the type R2T1X (X = halide, SO4-, CN , NO3, etc.) which resemble the isoelectronic mercury dialkyls R2Hg in being unaffected by air and water. The [TlMe2]+ ion is linear, but does not form an aquo complex like Me2Ga(H20)2. 

A net ionic equation describes the actual reaction between ions of compounds in aqueous solution. Ions that do not change at all during the reaction are omitted from... 

The most numerous cases of homogeneous catalysis are by certain ions or metal coordination compounds in aqueous solution and in biochemistry, where enzymes function catalytically. Many ionic effects are known. The hydronium ion H3O and the hydroxyl ion OH catalyze hydrolyses such as those of esters ferrous ion catalyzes the decomposition of hydrogen peroxide decomposition of nitramide is catalyzed by acetate ion. Other instances are inversion of sucrose by HCl, halogenation of acetone by H and OH , hydration of isobutene by acids, hydrolysis of esters by acids, and others. 

Charged particles must be free to move for a material to conduct an electric current. In the solid state, ionic compounds are nonconductors of electricity because of the fixed positions of the ions. However, in a liquid state or when dissolved in water, ionic compounds are electrical conductors because the ions are free to move. An ionic compound whose aqueous solution conducts an electric current is called an electrolyte. You will learn more about solutions of electrolytes in Chapter 15. 

Write the total ionic and net ionic equations for the reaction between each of the following pairs of compounds in aqueous solution. Then give the Lewis formula for each species in these equations, (a) HCN and NaOH (b) HCl and NaOH (c) CaCl2 and Na2C03. 

Clearfield [64CLE] reviewed the structural aspects of zirconium chemistry. One of the important findings of this review was the substantial amount of evidence that was presented for the absence of the zirconyl (ZrO ) ionic structure in aqueous solution and in solids. Even in monoclinic zirconium oxide, Zr-O-Zr bonds are present rather than the Zr=0 double bond. Many compounds in both aqueous solution and the solid state contain hydroxo-zirconium bridges (see Section V.2.2). Clearfield presented evidence of the moiety [Zr4(0H)g(H20)i6] occurring in both aqueous solution and the solid state and argued that measurements by Zielen and Connick [56Z1E/CON] to determine the stability of polymeric zirconium hydrolysis species confirmed the existence of this species in aqueous solution. 

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