Lead/ions/salts

The solid is essentially ionic, made up of Pb and Cl ions. The vapour contains bent molecules of PbCh (cf. SnCh). Lead chloride is precipitated when hydrochloric acid (or a solution of a chloride) is added to a cold solution of a lead(ll) salt. It dissolves in hot water but on cooling, is slowly precipitated in crystalline form. It dissolves in excess of concentrated hydrochloric acid to give the acid H2[Pb"Cl4]. 

If a metal ion of an insoluble chromate is added to a solution containing the dichromate ion. the chromate is precipitated for example with a soluble lead(II) salt ... 

The bridging by bromine prevents rotation about the remaining bond and back-side nucleophilic opening of the bromonium ion by bromide ion leads to the observed anti addition. Direct evidence for the existence of bromonium ions has been obtained from NMR measurements.31 A bromonium ion salt (with Br3 as the counterion) has been isolated from the reaction of bromine with the very hindered alkene adamantylide-neadamantane.32... 

The feasibility of the above reaction ensues from the data on the solubility products of lead sulfate and lead carbonate salts. Evidence abounds that both sulfate and carbonate ions are present. 

This wastewater stream contains lead (Pb) salts and chlorinated hydrocarbons generated from corrosion of the anodes as well as asbestos particles generated as a result of degradation of the diaphragm with use. Wastewater is also generated from the scrubber where the chlorine is wet scrubbed and from the ion exchange resin used to purify the brine solution. These wash water often contains dilute hydrochloric acid with small amounts of dissolved calcium magnesium and aluminum chloride. Like in other cells, the scrubber water also contributes to the wastewater stream. 

Inorganic lead ions are not known to be metabolized in the body but they are complexed by macromolecules. Lead that is not retained in the body is excreted principally by the kidney as salts or through biliary clearance into the gastrointestinal tract in the form of organometallic conjugates. 

Following the lead in the study of anionic polymerisations, several workers used common-ion salts to shift equilibrium (11) in attempts to determine kp and by means of... 

The disodium salt of ethylenediaminetetraacetic acid, also known as EDTA, has a great affinity for lead ions, Pb2+. Why Can you think of any useful applications of this chemistry ... 

A basic salt is a salt contains combined base as Pb(OH) Pb(C H302)2, a basic acetate of lead These salts may be regarded as foimed from the basic hydroxides by partial replacement of hydroxyl (e.g., HO—Zn—Q). They react like bases and, when soluble, ionize to yield hydroxyl ions. 

Salt. When compared on a molar basis, the mineral ion salts (ammonium, calcium, rubidium, copper, silver, lead, manganese, cobalt, potassium, and sodium, and cyclohexylamine salt) were as effective as the free gibberellic acid in promoting stem elongation (10,14). As shown in Figure 1, the potassium and zinc salts of A3 were as active as the acid in promoting the growth of d-1 dwarf maize. 

The greater affinity of humic acids for copper or lead ions is clearly reflected in the extraction values reported in Fig. 2.1. In particular, far less of the adsorbed material was displaced by the salt solutions. The amount of lead retrieved by these extractants, and also with the mineral acids and buffer solutions, exceeded the copper recoveries, so copper appears to be more firmly bound than lead on the humic acid samples studied. 

Each beaker contains a soluble salt, which means that each ionic salt will dissolve in the water. Crystalline Pb(N03)2, when added to water, dissolved. The same happened to KI. In each beaker, since the salts are soluble, the ions are dissolved in water and floating about. In the first beaker, if a lead ion encounters a nitrate ion, it may stick together briefly, but because the salt is soluble, it will quickly dissolve into solution again. The same is true for the KI beaker. If you dump some of each beaker into a third beaker, you are going to mix all four of the ions together like in Figure 11.2. 

One salt to examine is PbS04. Lead sulfate dissolves according to the following equation PbS04(s) <—> Pb2+(aq) + S042 (aq). The solubility product constant for lead sulfate can be written as KsP = [Pb2+][S042 ] /1. Notice that the solid was not included in the equilibrium constant expression. What concentration of lead and sulfate ions will you find in a saturated solution of lead sulfate at 298 K The solubility product constant for lead sulfate is 1.6 x 10-8. This means that the concentration of lead ions and sulfate ions is each 1.26 x 10-4M. 

A special case of reversible ionization of a hexacoordinate silicon complex has been described as a novel tautomeric equilibrium.41 It differs from the formation of siliconium-ion salts in that the positive charge resides on nitrogen, in a dimethylammonium cation, and not on silicon. The transsilylation of lg with 12 in equimolar concentrations leads to the pentacoordinate zwitterionic complex 13 (Eq. (10), Section II.B.5). However, when the molar ratio was 2 1, respectively, an equilibrium mixture of tautomers (58, 59) was obtained, as shown in Eq. (21). The same mixture was also obtained when a second mole-equivalent of lg was added to 13. 

The solubility of a dissolved non-electrolyte solute can be reduced by the addition of a salt. This phenomenon, known as the salting-out effect, is of practical importance for the isolation of organic compounds from their solutions. In the presence of a dissolved dissociated salt, a fraction of the solvent molecules becomes involved in solva-tional interaction with the ions of the electrolyte, whereby their activity is diminished, leading to salting-out of the dissolved non-electrolyte solute. In other words, the salting-out can be considered as the difference in solubility in two kinds of solvents, the ion-free and the ion-containing one [248]. 

Although the exact mechanism of the thermal, heat-induced decomposition of PVC remains unknown, most chemists agree that the chlorine atoms present in the polymer play an important role. Lead salts are added to PVC both to provide anions less reactive than chloride and to provide lead ions to combine with the released chloride ions. As a beneficial side effect, the lead... 

The solubility of lead chromate in water is exceedingly small indeed, the chromate is probably the least soluble salt of lead. It is practically insoluble also in dilute acetic acid consequently chromate ions in presence of acetic acid constitute a very delicate test for lead ions in solution. The solubility of lead chromate in water at 25° C. is about 10 grams per litre according to Kohlrausch, but von Hevesy and Paneth obtained the value 1-2 X 10 grams per litre by employing... 

Glattfeld and Hanke applied this procedure to the oxidation of maltose hydrate. An aqueous solution of the sugar was shaken with lead carbonate and bromine since lead bromide separated from the reaction mixture, only aeration was necessary to remove the excess bromine, and treatment with silver oxide and hydrogen sulfide removed the last bromide, silver and lead ions. The maltobionic acid was isolated as the calcium salt. Here the neutralization of the hydrobromic acid was beneficial in preventing any hydrolysis of the aldobionic acid. 

Lead(II) is a useful metal for such studies as it is relatively redox inert and has the ability to form complexes with a wide range of coordination numbers and with almost any donor atom type. Substituted triazacyclonanes (69)-(71) form 1 1 complexes with lead(II) and (72) forms a 1 2 complex in which two lead ions are coordinated, one in each of the distinct sites. In each case, the complexes were isolated as their (tetraphenyl)borate salts and in the cases where the complexes were characterized crystallographically, a close if type interaction was seen with one of the phenyl groups of the counterion (Scheme 19). ... 

At very negative potentials neither the tetraalkylammonium ions nor the metallic electrode are inert they combine to form reduced TAA-metals [7]. Tetraalkylammonium (TAA) metals are composed of quaternary ammonium ions, electrons, and a post-transistion metal such as Hg, Pb, Sn, Sb, Bi [5-18] or Pt [19] most of them have the composition R4N" MeJ [13] or R4N" Mc4 [20] and have been described as Zintl ion salts or Zintl phases [21,22]. They have been shown to be useful intermediates in the electrochemical reduction of certain substrates that are reducible with difficulty. On reduction of the quaternary ammonium salt, the initial layer of the metal compound is controlled by a two-dimensional nucleation, whereas the bulk phase is initiated by a three-dimensional nucleation and a growth controlled by the diffusion of R4N from the solution. In some cases (A-methylquinuclidinium (MQ" ) mercury) the catalytic efficiency of the initial layer is greater than that of the bulk phase [18], whereas in other cases (A, A-dimethylpyrrolidinium (DMP" ) lead) the opposite is found [16]. 

The limiting current density is an important parameter for the analysis of mass transfer controlled electrochemical processes and represents the maximum possible reaction rate for a given bulk reactant concentration and fluid flow pattern. During anodic metal dissolution, a mass transfer limiting current does not exist because the surface concentration of the dissolving ion (e.g., Cu + when the anode is composed of copper metal) increases with increasing current density, eventually leading to salt precipitation that blocks the electrode surface. 

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