Barium hydroxide, solubility

Compared to the hydroxides of calcium and strontiuim, barium hydroxide is the most water-soluble and also the strongest base. Additionally, barium hydroxide is more difficult to convert to the oxide by heating than are the corresponding hydroxides of calcium and strontium. Barium oxide is more readily converted to the peroxide than are the oxides of the other alkaline earths. 

Barium hydroxide is the strongest base and has the greatest water-solubility of the alkaline-earth elements. Barium hydroxide (barium hydrate, caustic baryta) exists as the octahydrate [12230-71 -6], Ba(OH)2 8H20, the monohydrate [22326-55-2], Ba(OH)2 H20, or as the anhydrous [17194-00-2] material, Ba(OH)2. The octahydrate and monohydrate have sp gr 2.18 and 3.74, respectively. The mp of the octahydrate and anhydrous are 77.9 °C and 407°C, respectively. 

The solubility of barium hydroxide in water at 20°C is 1.85 g/100 g water. A solution is made up of256 mg in 35.0 g of water. Is the solution saturated If not, how much more barium hydroxide needs to be added to make a saturated solution ... 

Hydrochloric acid and sulphuric acid are widely employed in the preparation of standard solutions of acids. Both of these are commercially available as concentrated solutions concentrated hydrochloric acid is about 10.5- 12M, and concentrated sulphuric acid is about 18M. By suitable dilution, solutions of any desired approximate concentration may be readily prepared. Hydrochloric acid is generally preferred, since most chlorides are soluble in water. Sulphuric acid forms insoluble salts with calcium and barium hydroxides for titration of hot liquids or for determinations which require boiling for some time with excess of acid, standard sulphuric acid is, however, preferable. Nitric acid is rarely employed, because it almost invariably contains a little nitrous acid, which has a destructive action upon many indicators. 

C04-0024. Determine whether the following salts are soluble or insoluble (a) sodium acetate (b) AgN03 (c) barium hydroxide (d) CaO (e) lead(II) sulfate (f) ZnCl2 and (g) manganese(II) sulfide. 

Strong bases include the oxides and hydroxides of the alkali metals and also the soluble oxides and hydroxides of the Group 2 metals, such as barium oxide and barium hydroxide. 

SOLUBILITY PRODUCT Barium hydroxide hexahydrate (Ba(0H)2-6H20),... 

Compounds Soluble—barium nitrate, barium sulfide, barium chloride, barium hydroxide, barium acetate insoluble—barium sulfate... 

Peterson and Scarrah 165) reported the transesterification of rapeseed oil by methanol in the presence of alkaline earth metal oxides and alkali metal carbonates at 333-336 K. They found that although MgO was not active for the transesterification reaction, CaO showed activity, which was enhanced by the addition of MgO. In contrast, Leclercq et al. 166) showed that the methanolysis of rapeseed oil could be carried out with MgO, although its activity depends strongly on the pretreatment temperature of this oxide. Thus, with MgO pre-treated at 823 K and a methanol to oil molar ratio of 75 at methanol reflux, a conversion of 37% with 97% selectivity to methyl esters was achieved after 1 h in a batch reactor. The authors 166) showed that the order of activity was Ba(OH)2 > MgO > NaCsX zeolite >MgAl mixed oxide. With the most active catalyst (Ba(OH)2), 81% oil conversion, with 97% selectivity to methyl esters after 1 h in a batch reactor was achieved. Gryglewicz 167) also showed that the transesterification of rapeseed oil with methanol could be catalyzed effectively by basic alkaline earth metal compounds such as calcium oxide, calcium methoxide, and barium hydroxide. Barium hydroxide was the most active catalyst, giving conversions of 75% after 30 min in a batch reactor. Calcium methoxide showed an intermediate activity, and CaO was the least active catalyst nevertheless, 95% conversion could be achieved after 2.5 h in a batch reactor. MgO and Ca(OH)2 showed no catalytic activity for rapeseed oil methanolysis. However, the transesterification reaction rate could be enhanced by the use of ultrasound as well as by introduction of an appropriate co-solvent such as THF to increase methanol solubility in the phase containing the rapeseed oil. 

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. 

Another catalyst which may also involve a homogeneous catalysis mechanism is barium hydroxide. Barium hydroxide has been reported to catalyze the methanolysis of rapeseed oil at 65°C with over 80% of oil conversion in less than an hour. " However, Ba(OH)2 shows non-negligible solubility in water, methanol and polyols. " For instance, in alcohols Ba(OH)2 can form barium alcoholates (RO Ba OH and RO Ba-OR). A barium alcoholate of formula... 

Rubidium acid salts are usually prepared from rubidium carbonate or hydroxide and the appropriate acid in aqueous solution, followed by precipitation of the crystals or evaporation to dryness. Rubidium sulfate is also prepared by the addition of a hot solution of barium hydroxide to a boiling solution of rubidium alum until all the aluminum is precipitated. The pH of the solution is 7.6 when the reaction is complete. Aluminum hydroxide and barium sulfate are removed by filtration, and rubidium sulfate is obtained by concentration and crystallization from the filtrate. Rubidium aluminum sulfate dodecahydrate [7488-54-2] (alum), RbA SO 12H20, is formed by sulfuric acid leaching of lepidolite ore. Rubidium alum is more soluble than cesium alum and less soluble than the other alkali alums. Fractional crystallization of Rb alum removes K, Na, and Li values, but concentrates the cesium value. Rubidium hydroxide, RbOH, is prepared by the reaction of rubidium sulfate and barium hydroxide in solution. The insoluble barium sulfate is removed by filtration. The solution of rubidium hydroxide can be evaporated partially in pure nickel or silver containers. Rubidium hydroxide is usually supplied as a 50% aqueous solution. Rubidium carbonate, Rb2C03, is readily formed by bubbling carbon dioxide through a solution of rubidium hydroxide, followed by evaporation to dryness in a fluorocarbon container. Other rubidium compounds can be formed in the laboratory by means of anion-exchange techniques. Table 4 lists some properties of common rubidium compounds. 

Tetrammino-palladous Hydroxide, [Pd(NII3)4](OH)2, may be obtained by decomposing the sulphate with barium hydroxide. It separates as a colourless crystalline substance which is soluble in water and has a strong alkaline reaction. The aqueous solution is capable of precipitating copper, iron, cobalt, and nickel from solutions of their salts, and it also decomposes ammonium salts. 

In 1818, A. Arfvedson 17 causticized lithium carbonate by means of calcium hydroxide, but the sparing solubility of lithium carbonate causes but a poor yield. L. Troost made the hydroxide by dissolving in water the oxide obtained by the combustion of the metal and C. G. Gmelin decomposed lithium sulphate by an eq. soln. of barium hydroxide. In either case, the soln. should.be evaporated rapidly to dryness in a silver vessel, and then fused. 

How can the oxides, peroxides, and hydroxides of the alkaline-earth metals be prepared What are the commercial names of calcium and barium hydroxide solutions How do the solubility, basic properties, and thermal stability of the hydroxides change in the series calcium-strontium-barium ... 

The product of nitration of dimethyloxamide is soluble in nitric acid and is separated by pouring the solution into water. It decomposes on treatment with concentrated sulphuric acid or on boiling with aqueous ammonia or barium hydroxide solution, forming the corresponding methylnitramine salt. Similarly, long-continued boiling in water results in complete decomposition, with the formation of oxalic acid and methylnitramine. 

Stabilization of a radical anion of humic acid may be caused by an adsorption effect. Bijl (3) observed that solid barium hydroxide octahydrate turned blue when placed in a solution of quinhydrone the blue solid was highly paramagnetic. Under the conditions we used for preparing these salts, insoluble sodium humate (with a large surface area) could have stabilized the anion radical by adsorption from the basic solution. Weiss and McNeil (18) observed a similar phenomenon with base soluble xanthenes, and proposed that biradicals may be formed in such a system. His compounds, however, do not appear to have the structural requirements to satisfy such a stabilized system. The recent report by Weber (29) on the spin content increase associated with the basification of a naphthoquinone-naphthohydroquinone system seems to parallel our observations quite closely. 

Barium hydroxide has also been used to recover sucrose from molasses, but when applied to lactose, no precipitate formed on addition of alkali. This indicates that the barium-lactose complex was more soluble than the calcium-lactose complex. Even addition of acetone at levels comprising 20% of the final volume gave a much lower recovery of lactose (Nickerson 1979). 

The procedure to be followed is the same as for the calcium salt except that about 180g of barium hydroxide 8-hydrate is employed, instead of the slaked lime. As the former is more soluble, some care should be exercised not to add too great an excess because the quantity of slurry... 

To determine the equivalent of an acid, a suitable quantity of it—determined by trial titrations—is dissolved in distilled water if soluble in water, and if insoluble in water in aqueous alcohol, or in alcohol free from acid. The average of a few readings which should agree to within 0-5% is taken, and the amount of acid necessary to neutralise 85-5 gms. of barium hydroxide calculated. 

A solution is saturated if it contains the maximum amount of solute that can possibly be dissolved in a solvent at the existing temperature and pressure conditions. If a solution is saturated, it need not be concentrated. Concentrated refers to the ratio of solute to solvent. A solution is concentrated if it contains a high ratio of solute to solvent. A solution is dilute if it contains a low ratio of solute to solvent. A solution of ammonia gas dissolved in water can be highly concentrated but not saturated. Ammonia gas dissolves easily in water. Barium hydroxide is slightly soluble. A saturated solution of barium hydroxide is very dilute. 

Most hydroxide compounds are insoluble, except alkali metal hydroxides and barium hydroxide [Ba(OH)2], which are soluble, and calcium hydroxide [Ca(OH)2] and strontium hydroxide [Sr(OH) 2], which are slightly soluble. 

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