Solubility barium salts

CH OfiSj, H2C(S03H)2- a colourless, crystalline solid which readily absorbs water vapour decomposes on distillation. The potassium salt is prepared by heating methylene chloride with an aqueous solution of potassium sulphite under pressure at 150-I60" C. The free acid is obtained by decomposing the sparingly soluble barium salt with sulphuric acid. The aryl esters are very stable, but the alkyl esters decompose on heating to give ethers. Resembles malonic acid in some of its reactions. 

The oxidation of cyctopentanone (Section 111,73) with dilute nitric acid gives glutaric acid accompanied by some succinic acid the latter is removed as the sparingly-soluble barium salt ... 

Toxicity. The toxicity of barium compounds depends on solubility (47—49). The free ion is readily absorbed from the lung and gastrointestinal tract. The mammalian intestinal mucosa is highly permeable to Ba " ions and is involved in the rapid flow of soluble barium salts into the blood. Barium is also deposited in the muscles where it remains for the first 30 h and then is slowly removed from the site (50). Very Httle is retained by the fiver, kidneys, or spleen and practically none by the brain, heart, and hair. 

Treatment. Treatment of poisoning from soluble barium salts may be preventive or curative (47,51). Preventive treatment involves inhibition of intestinal absorption by administering such soluble sulfates as magnesium or sodium, causing precipitation of barium sulfate in the alimentary tract. 

Two grams of the oU are saponified the portion insoluble in water separated by shaking with ether, and the aqueous solution neutralised with acetic acid. The solution is dUuted to 50 c.c. and 10 c.c. of cold saturated solution of barium chloride added. It is then warmed for two hours on a water-bath and allowed to cool. If a crystalline deposit is formed, the oil is to be considered adulterated, as the acids contained in normal lavender oil, acetic and butyric acids, give soluble barium salts. It is evident that this test will only detect those acids whose barium salts are insoluble. A more comprehensive test is therefore needed, as several other esters have since been employed for adulteration purposes. Glycerin acetate, prepared by the acetylation of glycerine, was first de-... 

The solubility guidelines can be used to design ways of making salts. Suppose that we want to prepare barium sulfate, BaSOq. This substance is opaque to X rays, so it is often used to visualize the intestinal tract. Patients are given a barium cocktail, and then the areas of interest are irradiated. Barium sulfate absorbs the X rays to give a picture of the intestines. Soluble barium salts are poisonous, but BaSOq is insoluble in water, so it can be administered safely. (Only 1.0 X 10" mol dissolves in 1 L ofwaterat25 °C.)... 

This equation may be interpreted to mean that any soluble barium salt will react with any soluble sulfate to produce (insoluble) barium sulfate. 

Ans. BaCI,. BatClO,),. or any other soluble barium salt. 

The flavianic acid can be recovered from its sparingly soluble barium salt as follows Decompose the salt with a slight excess of hot 20 per cent sulphuric acid, filter at the pump while hot, add some concentrated hydrochloric add to the clear filtrate, and allow the free sulphonic acid to crystallise. 

Now, if to the resulting supernatant liquid, which is nothing but a saturated solution of barium sulphate, an additional small quantity of either a soluble barium salt or a soluble sulphate is provided, a slight further precipitation may occur. 

From Eq. (a), it may be derived that if the concentration of Ba2+ ion is enhanced by the addition of a soluble barium salt, the concentration of sulphate ion should decrease simultaneously and conversely, that if the concentration of sulphate ion is enhanced by the addition of a soluble sulphate salt, the concentration of Ba2+ ion should decrease as their product almost remains constant. Evidently, this decrease in the concentration of the ions in either instance may be achieved by the combination of barium and sulphate ions to give rise to the insoluble barium sulphate thereby forcing the reaction towards completion. 

Barium azide may be prepared by reacting sodium azide with a soluble barium salt. The solution is concentrated to allow crystals grow. Crystals wdl explode if fully dried, or subject to friction. Product should be stored damp with ethanol. 

Barium hydroxide decomposes to barium oxide when heated to 800°C. Reaction with carbon dioxide gives barium carbonate. Its aqueous solution, being highly alkahne, undergoes neutrahzation reactions with acids. Thus, it forms barium sulfate and barium phosphate with sulfuric and phosphoric acids, respectively. Reaction with hydrogen sulfide produces barium sulfide. Precipitation of many insoluble, or less soluble barium salts, may result from double decomposition reaction when Ba(OH)2 aqueous solution is mixed with many solutions of other metal salts. 

You have seen that barium sulfate is an insoluble salt (p. 125). Therefore, if you take a solution of a suspected sulfate and add it to a solution of a soluble barium salt (such as barium chloride) then a white precipitate of barium sulfate will be produced. 

The sulfate may be brushed up and treated as normal refuse. Soluble barium salts should be scooped up and treated as for waste disposal. Wash the spill area thoroughly with water. 

Numerous factors may be involved with the toxic substance itself. If the substance is a toxic heavy metal cation, the nature of the anion with which it is associated can be crucial. For example, barium ion, Ba2+, in the form of insoluble barium sulfate, BaS04, is routinely used as an x-ray opaque agent in the gastrointestinal tract for diagnostic purposes (barium enema x-ray). This is a safe procedure however, soluble barium salts such as BaCl2 are deadly poisons when introduced into the gastrointestinal tract. 

The manufacture of soluble barium salts involves treatment of the mineral (usually barite) with the relevant acid, filtration to remove insoluble impurities, and crystallization of the salt. 

The high-temperature reduction of barium sulfate with coke yields the water-soluble barium sulfide (BaS), which is subsequently leached out. Treatment of barium sulfide with the relevant chemical yields the desired barium salt. Purification of the product is complicated by the impurities introduced in the coke. Pure barium carbonate and barium sulfate are made by precipitation from solutions of water-soluble barium salts. 

Tetranitrophenol forms by the action of 50% nitric acid followed by a 63% acid on diquinoyltrioxime at a temperature lower than the room temperature. By neutralizing the solution a sparingly soluble potassium salt is precipitated, which in turn may be converted by double decomposition into a still less soluble barium salt. From the latter, by the action of a calculated quantity of sulphuric acid, free tetranitrophenol may be obtained. 

These constants determine the titration exponents pH and the best indicators for the successive hydrions. The acid can be titrated as dibasic, using methyl yellow, methyl orange or bromophenol blue, and as tetrabasic using phenolphthalein, thymolphthalein or thymol blue in the presence of a moderate excess of soluble barium salt. The values of pH in the partly neutralised acid were corrected for the salt error, and the constants Kz and jfiT4 which prevail in solutions of low concentration were thus deduced —6... 

Barium carbonyl ferrocyanide, Ba3[Fe(CN)5.C0]2llH20, is readily prepared by decomposing the copper salt with a soluble barium salt, or by neutralising the free acid with barium hydroxide. It loses 10 molecules of water at 19° C. in vacuo, and becomes anhydrous at 130° C. The heats of solution are —6... 

DFG MAK Soluble Compounds 0.5 mg/m DOT CLASSIFICATION 6.1 Label Poison SAFETY PROFILE The chromate is a human carcinogen. The soluble barium salts, such as the chloride and sulfide, are poisonous when ingested. The insoluble sulfate used in radiography is not acutely toxic. See also BARIUM SULFATE. Few cases of industrial systemic poisoning have been reported, but one investigator describes a fatal case of poisoning attributed... 

Barium is a constituent of alloys that are used for spark plugs because of the ease with which it emits electrons when heated. It is used as a degassing agent for vacuum tubes. A slurry of finely divided barium sulfate, BaS04, is used to coat the gastrointestinal tract in preparation for X-ray photographs because it absorbs X-rays so well. It is so insoluble that it is not poisonous all soluble barium salts are very toxic. 

Nephelometry, a further technique of colorimetry is also related to the Lambert-Beer law. This method consists of forming a precipitate and from the light absorbed at a given wavelength, to determine the concentration of the precursor. For example, to measure a sulphate ion, a soluble barium salt is added. A sulfate precipitate of barium is formed of which the absorbance is measured following stabilization with a hydrosoluble polymer such as Tween . 

CARBONIC ACID, BARIUM SALT (513-77-9) BaCOj Noncombustible solid. The aqueous solution is basic. Dissolves in most acids except sulfuric acid with release of CO2 gas. This could be dangerous in a confined space. Incompatible with finely divided alxuninum bromine trifluoride fluorine, 2-furanpercarboxylic acid magnesium, oxidizers, sodium azide silicon strong alkalis. Decomposes above 2372°F/1300°C, releasing COj and soluble barium salts including barium oxide. On small fires, use dry chemical powder (such as Purple-K-Powder), foam, or CO2 extinguishers. 

How may a soluble barium salt be distinguished from a soluble calcium or strontium salt ... 

Some of the toxic effects of soluble barium salts can be explained by interactions of the barium ions with potassium ions. Because of the similar ionic radii of Ba " and K ions, the latter can occupy the outflow canals of cells for periods 10000-to 100 000-fold longer than can K" " ions (Miller 1987). In this manner, the outflow... 

The Canadian Council of Ministers of the Environment recommends an interim soil quality criterion of 750 mg kg for agricultural use (Anonymous 1999). The toxic action of barium compounds is determined by their solubility, and the only risk deriving from near-insoluble barium sulfate is that of soluble barium salts present as impurities. Hence, the concentration of acid-soluble substances in barium sulfate for pharma-... 

II) We need to mix a solution of a soluble barium salt (such as barium ethanoate, (CH3C00")2 Ba ) with a solution of a soluble sulfate (such as magnesium sulfate, Mg2, S0 -). 

Barium poisonings are uncommon and usually result from accidental contamination of food sources, suicidal ingestion, or occupational inhalation exposure. The water-soluble barium salts (acetate, carbonate, chloride, fluoride, hydroxide, nitrate, and sulfide) are highly toxic, whereas the insoluble salt, barium sulfate, is nontoxic because it is not absorbed. Soluble barium salts are found in depilatories, fireworks, ceramic glazes, and rodenticides and are used in the manufacture of glass and in dyeing textiles. Barium sulfide and polysulfide may also produce hydrogen sulfide toxicity (see p 224). 

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