Solubility lead iodide

Lead Iodide. Lead diiodide, Pbl2, forms a powder of yellow hexagonal crystals some physical properties are given in Table 1. Lead diiodide is soluble in alkaUes and potassium iodide, and insoluble in alcohol. It is made by treating a water-soluble lead compound with hydroiodic acid or a soluble metal iodide. It is readily purified by recrystaUization in water. 

Background Lead iodide is relatively insoluble, with a solubility of less than 0.002 M at 20°C. Lead iodide dissolved in water is represented as ... 

Lead Iodide. Add a potassium iodide solution to one of lead acetate. What is observed Pour off a part of the solution with the precipitate (about 1 ml) into a beaker, add 10-15 ml of water acidified with acetic acid, and heat the solution. What is its colour Cool the solution. Explain the observed phenomena. Compare the solubility of lead iodide and chloride in water. How does it change with the temperature ... 

Those submicron particulates which enter the alveolar sacs may undergo various degrees of absorption, depending upon the solubility of their components, or are transported to the base of the ciliated bronchiolar epithelium (54). Alveolar absorptive efficiency for most trace elements is 50-80% (50). Retention or absorption is not necessarily a simple function of solubility. Silver iodide, for example, is rapidly absorbed from the lungs even though it is weakly soluble in water (56). Likewise, insoluble elemental lead deposited in the respiratory passages is absorbed, but the mechanism involved remains to be elucidated (49). Vanadium probably accumulates in human lungs in insoluble forms... 

All metallic iodides except silver iodide, mercurous iodide, mercuric iodide, lead iodide, cuprous nidide. thallium iodide, and palladium iodide, are soluble. The iodides of antimony, bismuth, tin require a little free acid to keep them in solulion. 

Precipitation reactions are processes in which soluble reactants yield an insoluble solid product that drops out of the solution. Formation of this stable product removes material from the aqueous solution and provides the driving force for the reaction. Most precipitations take place when the anions and cations of two ionic compounds change partners. For example, an aqueous solution of lead(II) nitrate reacts with an aqueous solution of potassium iodide to yield an aqueous solution of potassium nitrate plus an insoluble yellow precipitate of lead iodide ... 

Lead carbonate and lead iodide are insoluble. Which two soluble salts could you use in the preparation of each substance Write... 

Lead acetate Potassium dichromate and concentrated sulfuric acid Sodium nitrite Copper sulfate Mercury (II) chloride Yellow precipitate of lead iodide soluble in excess hot water Liberation of iodine Liberation of iodine Brown mixed precipitate Scarlet precipitate of mercury (II) iodide... 

Lead iodide (PbL) dissolves in water with solubility product... 

The solubility rules indicate that lead iodide is insoluble and will form as a precipitate. The unbalanced net ionic equation is then ... 

When we consider the solubility of a salt in which the ions are of different valence, as for example lead iodide Pbl2 Pb++ + I- + I-, the product must include as many concentrations as there are ions to make the neutral molecule. Thus the solubility... 

This equation only shows the ions that are actually involved in the reaction. It also helps to point out other reactions that are possible. For example, any soluble lead salt, when combined with any soluble iodide salt, will produce the insoluble lead (II) iodide. 

Sr2+, Ba2+, Ra2+, and Pb2+ are insoluble, but most other sulfate compounds are soluble. Lead(II) iodide is insoluble. 

IV.16 IODIDES, I Solubility The solubilities of the iodides are similar to the chloride and bromides. Silver, mercury(I), mercury(II), copper(I), and lead iodides are the least soluble salts. These reactions can be studied with a O 1m solution of potassium iodide, KI. 

Lead acetate solution yellow precipitate of lead iodide, Pbl2, soluble in much hot water forming a colourless solution, and yielding golden-yellow plates ( spangles ) on cooling. 

We can state the resulting problem as follows What is the solubility of solid Pbl2 in a 3.33 X 10 2 M Nal solution The lead iodide dissolves according to the equation... 

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. 

Lead triphenyl iodide. —If the mother-liquors of the above bromide be treated with potassium iodide, and the product obtained crystallised from water, the iodide separates in pale yellow prisms, which sinter at 189 C. and melt sharply at 142 C. to a canary yellow liquid, which soon deposits lead iodide. It is difficultly soluble in liot methyl alcohol, and insoluble in water, and is distinguished from all the other lead aryl or alkyl iodides by its stability. It does not appear to yield an oxide with alcoholic sodium or potassium hydroxide, but a white precipitate is thrown down, this yielding lead triphenyl chloride with 50 per cent, hydrochloric acid. 

The solubility of lead iodide at this temperature is about 1 mmol/L. At the temperature of the experiment the precipitate dissolves and crystallises out again on... 

Because of the extremely low solubility product of lead iodide at room temperature === 3 X 10" ) it is only necessary to filter off the contents of the flask, to wash the precipitate several times with water and to transfer it to a break-proof vessel used for collecting less toxic inorganic waste. The waste water can be flushed down the drain. 

Calculate molar solubilities, concentrations of constituent ions, and solubilities in grams per liter for the following compounds at 25°C (a) Zn(CN)2, zinc cyanide (b) Pbl2, lead iodide (c) Pb3(As04)2, lead(II) arsenate (d) Hg2C03, mercury(I) carbonate [the formula for the mercury(I) ion isHg22 + ]. 

However, a reduction in the complexation ability of the melt-anion leads to a shift in the equilibrium (3.6.3) to the left, which finally results in a reduction in the metal-oxide s solubility. The substitution of bromide ions by iodide ions (transfer from bromide to iodide-melts) leads to the strengthening of the basic properties (which cause a decrease in the oxide solubility) and of the complexation ability (which results in the solubility increase). For molten Csl, the simultaneous action of both factors leads to an increase in the metal-oxide solubilities. However, iodide ion belongs to the group of soft bases, and this is the main reason for the solubilities of oxides in iodide-melts remaining lower than that in the molten alkali-metal chlorides. 

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