Solubility, lead compounds

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. 

Those who use recreational shooting ranges may be exposed to lead and soluble lead compounds, such as carbonates and sulfates, in soil. Surface... 

Again, there is insufficient evidence to draw conclusions, and the test results are difficult to explain. The lost lead from the petroleum ether layer could have been adsorbed on to the surface of the separating funnel and/or concentrated at the petroleum ether/water interface. A small amount of lead did enter the water layer in tests 2 and 3 but none in test 1. This could be due to a small proportion of the discharge residue containing a water-soluble lead compound or a small number of insoluble lead-containing particles finding their way into suspension in the water layer. 

Soluble Lead Compounds are often formed when lead is subjected to the action of water containing much gas, e.. air and carbon dioxide. 

Lead forms a thin surface layer of oxide in air. This oxide slowly changes to a basic carbonate. Hard water forms a similar coating on lead, which protects the water from contamination with soluble lead compounds. Soft water dissolves appreciable amounts of lead, which is poisonous for this reason lead pipes cannot be used to carry drinking water. 

Lead interacts with water producing hydroxide Pb(OH)2. In hard water lead is coated with film, preventing water from being polluted with soluble lead compounds. Detectable lead amount dissolves in distilled water resulting in water poisoning. 

The Information available (h4), (15) and (S4) on the solubility of the common soluble lead compounds is shown In Table lil. 

E.g. any work activity involving a wide variety of lead compounds (other than low solubility lead compounds). 

Low-solubility Glaze. The Potteries etc (Modifications) Regulations 1990 (S.I. 305) define this as a glaze which does not yield to dilute HCl more than 5% of its dry weight of a soluble lead compound, when determined in accordance with an approved method see lead solubility test (q.V.). for the original approval method. 

Other Compounds As we should expect from the solubility guidelines (Table 5.1), one of the few soluble lead compounds is lead(Il) nitrate, Pb(N03)2. It is formed in the reaction of Pb02 with nitric acid, as shown below ... 

When a soluble lead compound is added to a solution containing primarily orange dichromate ion, yellow lead chromate precipitates. Describe the equilibria involved. 

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