Lead chloride, solubility product

Lead tri-n-butyl chloride is obtained from magnesium butyl iodide, and lead chloride, the product being treated with hydrogen chloride as above. It forms colourless, flat needles which melt to a clear liquid at 109° to 110° C., and have a similar solubility to the propyl compound. The hydroxide is prepared by dissolving the chloride in aqueous alcohol and shaking with silver oxide. The solution in water ha an alkaline reaction, and absorbs carbon dioxide from the air. When treated with hydrogen bromide a white precipitate of lead iri-n-butyl bromide separates, which may be recrystallised from ether or chloroform. 

A precipitation reaction occurs when two or more soluble species combine to form an insoluble product that we call a precipitate. The most common precipitation reaction is a metathesis reaction, in which two soluble ionic compounds exchange parts. When a solution of lead nitrate is added to a solution of potassium chloride, for example, a precipitate of lead chloride forms. We usually write the balanced reaction as a net ionic equation, in which only the precipitate and those ions involved in the reaction are included. Thus, the precipitation of PbCl2 is written as... 

C18-0074. For the following salts, write a balanced equation showing the solubility equilibrium and write the solubility product expression for each (a) lead(II) chloride (b) magnesium carbonate (c) nickel(II) hydroxide and (d) silver acetate. 

Often it is possible to use approximate methods to avoid the tedium of solving Equation 1.5. In this problem, the small value of the solubility product tells us that the final concentration of the chloride ions will not be affected much by the dissolved silver chloride. So if we write [Cl-] = 0.01 + x 0.01, Equation 1.4 reduces to O.Olx = 1.56 x 10 10, which leads to the same final answer (to the number of significant digits used here). It is often a good strategy to try an approximation, obtain a (tentative) answer, then plug the answer back into the original equation to verify its accuracy. 

Cubic and higher order polynomial expressions also arise naturally in a wide range of problems in chemistry, particularly in solubility and equilibrium problems. If we try to dissolve lead (II) chloride (PbCl2) instead of silver chloride, the solubility product expression becomes... 

Deschamps, Pierre, and Charreton, Barthe. Determination of the solubility products of the hydroxide and basic chlorides of lead. Acad. Sci. Comptes Rendus 232, 162-163 (1951). 

This equation is the equilibrium expression Avhich holds for all solutions that are saturated with lead chloride. We see that the product of the concentration of the lead ion and the square of the concentration of the chloride ion is equal to a constant, This constant (which has a constant value at a given temperature, but in general will change somewhat with the temperature) is called the solubility product of lead chloride. The solubility-product equation may be used to calculate the solubility oi lead chloride in solutions containing extra lead ions or extra ebibride ions. 

Example 1. What is the value of the solubility product of lead chloride at 20 C ... 

The product of the ion concentrations, with the concentration of chloride ion squared, is equal to the solubility product, for every saturated solution of lead chloride. Using the numerical value of from Example l, we may accordingly write... 

Would lead chloride or lead iodide precipitate first if a solution of lead acetate were added drop by drop to a solution 1 M in chloride ion and 1 M in iodide ion What would be the composition of the solution when the second salt began to precipitate The solubility products are given in Table 22-1. 

Calculate the solubility-product constant, Ksp, of lead(II) chloride, PbCl2, which has a solubility of 1.00 g/100.0 g H2O at a temperature other than 25 °C. 

In a batch-wise operation, the product formed at the beginning of the precipitation is different from that formed at the end of the process and the final product is expected to be a mixture that is mostly suboptimal. Thus, in forward precipitation the pH rises gradually and, as expected for a product produced under acidic or neutral conditions, the material is rich in counterions like carbonate, nitrate, chloride, and sulfate. Extensive aging at higher pH is required to convert the material to a hydroxide-like precipitate. In addition, the least-soluble product will precipitate first leading to a sometimes undesirable... 

Since many metals and metal oxides dissolve easily in hydrochloric acid, a great number of analytical and preparative methods utilize chloride solutions. Therefore, it is of considerable practical interest to ascertain the composition of the hydrolyzed species prevailing in chloride media. We intend to determine also the compositions and the solubility products of the basic salts which are the ultimate products of the hydrolysis process. The study of the solubilty equilibria may lead to the development of new methods for the separation of metal ions and it may prove to be useful to explain the analytical data obtained in sea water. 

Each of the products whose synthesis is illustrated in Schemes 6.2 and 6.3 is a coloured cationic species. When the counteranion is chloride, the products are water-soluble and useful as basic (cationic) dyes for the eoloration of acrylic fibres. Precipitation of cationic dyes of these types from aqueous solution using large polymeric counteranions, notably phosphomolybdates, phosphotungstates and phos-phomolybdotungstates, leads to a range of highly insoluble red. 

Interestingly, sonication also improves the reverse reduction using cobalt (II) chloride.200 The oxidation of triarylbismuthines to their oxides by the usual reagents (hydrogen peroxide, permanganate, etc.) leads to decomposition products or a polymeric compound. Using iodosylbenzene under sonication, a soluble oxide can be prepared (Eq. 72).20i... 

A fresh lead surface slowly oxidizes into a thin, protective lead oxide (PbO) that stops further oxidation of the metal. Lead gives satisfactory resistance to corrosion in rural, marine, and industrial environments. The corrosion rate data for lead is shown as 0.5-0.7 pm/y in industrial (New York, NY), 1.2-2.2 pm/y in marine (Kure Beach, NC), and 1.05-1.85 pm/y in rural (State College, PA) [6]. Lead corrosion products in such environments, in addition to lead oxide, are sulfate, chloride, and carbonate, with lead chloride being the most soluble of all four products (see Table 1). However, lead in outdoor exposures was found to produce sulfate (PbS04) and/or carbonate (PbC03), and indoor exposures lead carboxylates. The primary atmospheric agents responsible for degradation of lead are SO2, CO2, and carboxylic acid [7]. The corrosion rate of chemical lead in Key West, Florida, and La Jolla, California is 0.58 and 0.53 pm/y (0.023 and 0.021 mpy), respectively [2]. 

In the calculation of the molar solubility of a compound such as leadfll) chloride, PbCb, given its solubility produet constant, the concentration of the ehloride ion. Cl", is exactly twice the concentration of the lead(II) ion, Pb. In the solubility product constant expression, this doubled concentration is also squared. However, when lead(II) chloride is precipitated by the combining of solutions of lead(II) nitrate, Pb(N03)2, and potassium chloride, KCl, the concentration of the chloride ion is not doubled before it is squared. Explain this difference. 

TSeT)2-halides combine high room temperature conductivity (o = 2500 Qcm ) with high thermal stability up to over 250 °C (see Fig. l).They are, however, practically insoluble even in exotic organic solvents. Only the donor TSeT itself shows limited solubility in high boiling polar solvents. Until recently pure 2 1 halides could only be made by electrocrystallization in nitrobenzene in the presence of an organic ammonium halide as electrolyte. Chemical pathways like oxidation with Cl2-gas or ferrous chloride lead to impure products mainly due to overoxidation of the donor. 

This metal-buffering is important when hydrolysis or insolubility limits the attainable free metal ion concentration. Thus, in toxicity studies of lead ion, the presence of phosphate and chloride ions in the physiological media and the very small solubility products of Pb3(P04)2 (lO ), PbHP04 (10 ) and PbCl2 severely limit the possible concentration of free lead ion. It is not feasible to add directly to the medium a soluble lead salt, such as the nitrate, in sufficiently small amounts that precipitation can be avoided but it is practicable to calculate the lowest value of pPb that would not result in precipitation and to use chelating agents to maintain this level in the system. 

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