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Dissolving precipitates

Here again the simple formulation [Sb ] is used to represent all the cationic species present.) The hydrolysis is reversible and the precipitate dissolves in hydrochloric acid and the trichloride is reformed. This reaction is in sharp contrast to the reactions of phosphorus(III) chloride. [Pg.253]

Solutions of many antimony and bismuth salts hydrolyse when diluted the cationic species then present will usually form a precipitate with any anion present. Addition of the appropriate acid suppresses the hydrolysis, reverses the reaction and the precipitate dissolves. This reaction indicates the presence of a bismuth or an antimony salt. [Pg.254]

To a few drops of formalin solution add a few drops of dinitro-phenylhydrazine reagent A (p. 263) a yellow precipitate is produced in the cold. Acetaldehyde and acetone give orange-coloured precipitates. Dissolve water-insoluble compounds e.g-y benzaldehyde, salicylalde-hyde, acetophenone and benzophenone) in a small volume of methanol before adding reagent B. With benzophenone the precipitate forms slowly. [Pg.334]

Brucke s reagent (protein precipitant) dissolve 50 g of K1 in 500 mL of water, saturate with Hglj (about 120 g), and dilute to 1 liter. [Pg.1189]

Occlusions are minimized by maintaining the precipitate in equilibrium with its supernatant solution for an extended time. This process is called digestion and may be carried out at room temperature or at an elevated temperature. During digestion, the dynamic nature of the solubility-precipitation equilibrium, in which the precipitate dissolves and re-forms, ensures that occluded material is eventually exposed to the supernatant solution. Since the rate of dissolution and reprecipitation are slow, the chance of forming new occlusions is minimal. [Pg.239]

Write balanced equations to explain why each of the following precipitates dissolves in strong acid. [Pg.441]

Write balanced net ionic equations to explain why a precipitate dissolves in... [Pg.445]

A solution of potassium dichromate is made basic with sodium hydroxide the color changes from red to yellow. Addition of silver nitrate to the yellow solution gives a precipitate. This precipitate dissolves in concentrated ammonia but re-forms when nitric acid is added. Write balanced net ionic equations for all the reactions in this sequence. [Pg.553]

The precipitate dissolves upon the addition of excess of potassium cyanide, the complex ion [Ag(CN)2] being produced ... [Pg.50]

Nickel may be determined in the presence of a large excess of iron(III) in weakly acidic solution by adding EDTA and triethanolamine the intense brown precipitate dissolves upon the addition of aqueous sodium hydroxide to yield a colourless solution. The iron(III) is present as the triethanolamine complex and only the nickel is complexed by the EDTA. The excess of EDTA is back-titrated with standard calcium chloride solution in the presence of thymolphthalexone indicator. The colour change is from colourless or very pale blue to an intense blue. The nickel-EDTA complex has a faint blue colour the solution should contain less than 35 mg of nickel per 100 mL. [Pg.336]

Some precipitates dissolve when the temperature is changed. This strategy is used to purify precipitates. The mixture is heated to dissolve the solid and filtered to remove insoluble impurities. The solid is then allowed to re-form as the solution cools and is removed from the solution in a second filtration. Complex ion formation (Section 11.13) can also be used to dissolve metal ions. [Pg.593]

If enough ammonia is added to a precipitate of silver halide, all the precipitate dissolves. A similar procedure is used to remove the silver halide emulsion from an... [Pg.593]

FIGURE 11.22 When ammonia is added to a silver chloride precipitate, the precipitate dissolves. However, when ammonia is added to a precipitate of mercury(l) chloride, mercury metal and mercury(ll) ions are formed in a redox reaction and the mass turns gray. Left to right silver chloride in water, silver chloride in aqueous ammonia, mercury(l) chloride in water, and mercury(l) chloride in aqueous ammonia. [Pg.596]

At this point, the silver and mercury(I) chlorides remain as precipitates. When aqueous ammonia is added to the solid mixture, the silver precipitate dissolves as the soluble complex ion Ag(NH3)2+ forms ... [Pg.596]

Upon addition of sodium thiosulfate solution, the AgBr precipitate dissolves, because S2 03 forms a very strong complex with Ag. This ligand is capable of dissolving AgBr ... [Pg.1330]

Chemical precipitation is used in porcelain enameling to precipitate dissolved metals and phosphates. Chemical precipitation can be utilized to permit removal of metal ions such as iron, lead, tin, copper, zinc, cadmium, aluminum, mercury, manganese, cobalt, antimony, arsenic, beryllium, molybdenum, and trivalent chromium. Removal efficiency can approach 100% for the reduction of heavy metal ions. Porcelain enameling plants commonly use lime, caustic, and carbonate for chemical precipitation and pH adjustment. Coagulants used in the industry include alum, ferric chloride, ferric sulfate, and polymers.10-12... [Pg.329]

A heavy precipitate composed of potassium coumarilate and potassium bromide may appear if the steam distillation has been very efficient. The precipitate dissolves during the addition of hydrochloric acid. [Pg.80]

The only Zr(0) carbonyl complex has been prepared by Wreford and co-workers. When ZrCl4 was treated with l,2-bis(dimethyl-phosphino)ethane (dmpe), and then subsequently reduced with sodium amalgam in the presence of 1,3-butadiene, the dmpe bridged dimer, [(t/-C4H6)2Zr(dmpe)]2(dmpe) (65), resulted (114). The brown crystalline dimer 65 was found to be in equilibrium with the 16-e- coordinatively unsaturated complex, (tj-C4H6)2Zr(dmpe) (66), and free dmpe. When toluene solutions of 65 were exposed to CO at —45°C, 1 equivalent of CO per equivalent of Zr was consumed and the CO adduct (r/-C4H6)2Zr-(dmpe)(CO) (67) precipitated as a yellow solid. If these mixtures were allowed to warm above -22°C under vacuum, the precipitate dissolved and the consumed CO evolved (114). Complex 67 could be isolated by... [Pg.373]

To 1.0 mL of the test solution, add 3.0 mL of dilute sodium hydroxide solution and 3.0 mL of water and 1.0 mL of a 100 g/L solution of cobalt nitrate. The test is positive if violet precipitate is formed. The precipitate dissolves in methylene chloride [10,11]. [Pg.221]

The behavior of Zn2+ in liquid ammonia is analogous to that in water. First a precipitate of Zn(NH2)2 forms when an amide is added, but the precipitate dissolves when either a solution containing NH4+ or Nl l2 is added. This behavior can be shown as follows ... [Pg.335]

Coordinate bonds between metals and ligands result in the formation of complexes under many different types of conditions. In some cases, complexes form in the gas phase, and the number of known solid complexes is enormous. However, it is in solutions that many of the effects of complex formation are so important. For example, in qualitative analysis, AgCl precipitates when a solution of HC1 is added to one containing Ag+. When aqueous ammonia is added, the precipitate dissolves as a result of the formation of a complex,... [Pg.671]

To determine 63 Ni in seawater the nickel was adsorbed on to hydrous manganese dioxide and the precipitate dissolved in hydrochloric acid. The nickel was then extracted with diethyldithiocarbamate in chloroform and determined by liquid scintillation counting [527]. [Pg.209]

Iron Iron co-precipitated with tetraphenyl boron/1,10-phenanthroline, precipitate dissolved in ammoniacal ethanol Miscellaneous [568]... [Pg.293]

Nickel Nickel is co-precipitaed with sodium diethyldithiocarba-mate and the precipitate dissolved in nitric acid AAS 0.5 ng/1 [897]... [Pg.296]

Plutonium Pu co-precipitated with ferric hydroxide, precipitate dissolved in acid Anion exchange chromatography - [903,904]... [Pg.296]

Selenium Selenium co-precipitated with Fe(OH)3, precipitate dissolved in hydrochloric acid, converted to 5-nitro- piazselenol Gas chromatography with electron capture detector 5 ng/1 [907]... [Pg.297]

Uranium coprecipitated with aluminium phosphate, precipitate dissolved in nitric acid Adsorption onto colloidal ferric hydroxide... [Pg.298]


See other pages where Dissolving precipitates is mentioned: [Pg.77]    [Pg.479]    [Pg.223]    [Pg.166]    [Pg.271]    [Pg.311]    [Pg.129]    [Pg.561]    [Pg.76]    [Pg.549]    [Pg.195]    [Pg.63]    [Pg.1015]    [Pg.140]    [Pg.141]    [Pg.215]    [Pg.1328]    [Pg.479]    [Pg.584]    [Pg.132]    [Pg.335]    [Pg.357]   
See also in sourсe #XX -- [ Pg.380 ]




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Dissolving and Precipitating Contaminants

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