Silver chloride oxalate

Nitropropane Nitrosyl fluoride Nitrosyl perchlorate Nitrourea Nitrous acid Nitryl chloride Oxalic acid See under Nitromethane chlorosulfonic acid, oleum Haloalkenes, metals, nonmetals Acetones, amines, diethyl ether, metal salts, organic materials Mercury(II) and silver salts Phosphine, phosphorus trichloride, silver nitrate, semicarbazone Ammonia, sulfur trioxide, tin(IV) bromide and iodide Furfuryl alcohol, silver, mercury, sodium chlorate, sodium chlorite, sodium hypochlorite... 

The oxalate, [Cr(NH3)4H20.Cl]C204, separates in violet-red crystals on the addition of potassium oxalate to a solution of the chloride. It is sparingly soluble in water, and the solution gives a precipitate of calcium oxalate with calcium chloride. A freshly prepared solution of the salt in nitric acid gives no precipitate with silver nitrate. The chlorine atom in the chloro-aquo-salts is within the complex, and hence silver chloride is not at first precipitated by silver nitrate on boiling with nitric acid and silver nitrate, however, chlorine is precipitated as silver chloride. 

Often, greater accuracy may be obtained, as in Volhard type titration, by performing a back titration of the excess silver ions. In such a case, a measured amount of standard silver nitrate solution is added in excess to a measured amount of sample. The excess Ag+ that remains after it reacts with the analyte is then measured by back titration with standard potassium thiocyanate (KSCN). If the silver salt of the analyte ion is more soluble than silver thiocyanate (AgSCN), the former should be filtered off from the solution. Otherwise, a low value error can occur due to overconsumption of thiocyanate ion. Thus, for the determination of ions (such as cyanide, carbonate, chromate, chloride, oxalate, phosphate, and sulfide, the silver salts of which are all more soluble than AgSCN), remove the silver salts before the back titration of excess Ag.+ On the other hand, such removal of silver salt is not necesary in the Volhard titration for ions such as bromide, iodide, cyanate, thiocyanate, and arsenate, because the silver salts of these ions are less soluble than AgSCN, and will not cause ary error. In the determination of chloride by Volhard titration, the solution should be made strongly acidic to prevent interference from carbonate, oxalate, and arsenate, while for bromide and iodide analysis titration is carried out in neutral media. 

Nielsen compared the induction periods observed by various investigators for several precipitates. He reported the induction period for silver chloride to be inversely proportional to the fifth power of the initial concentration after mixing. Similarly, induction periods for silver chromate, calcium fluoride, calcium oxalate, and potassium perchlorate are inversely proportional to the 4.7,9,3.3, and 2.6 powers of the initial concentrations. For barium sulfate, on the other hand, a variety of discordant values has been observed. La Mer summarized the data of two groups of observers, covering a range of concentrations (Figure 8-1). 

Microwave laboratory ovens are currently quite popular. Where applicable, these greatly shorten drying cycles. For example, slurry samples that require 12 to 16 hours for drying in a conventional oven are reported to be dried within 5 to 6 minutes in a microwave oven. The time needed to dry silver chloride, calcium oxalate, and barium sulfate precipitates for gravimetric analysis is also shortened significantly. ... 

Separation of Pd with a collector. To the sample solution (-100 ml) in 0.1 M HCl, containing not more than 50 pg of Pd and heated to 80°C, add a macerated filter paper and 1 ml of 5% oxalic acid solution. Keep the solution at 80°C for 1 h, then allow it to cool. Filter off the precipitate of elemental gold and silver chloride together with the paper. To the filtrate add successively 2 mg of nickel (as its sulphate solution), 2 ml of 20% potassium sodium tartrate solution [to mask Fe(IIl), Al, Ti, etc.], 2 g of sodium acetate, 1 ml of 0.1 A/ EDTA, and 2 ml of the H2Dm solution (pH -6.5). After 30 min, filter off the precipitate of nickel- and palladium dimethylglyoximates. Wash the precipitate from the filter paper into a beaker, add 1 ml of cone. HCl, and evaporate to 5-10 ml, depending on the quantity of Pd in the solution. 

Characters and Tests.—Colourless, rhomhoidal crystalline plates, cool saline taste, sparingly soluble in cold water. Its aqueous solution is not affected by silver nitrate or ammonium oxalate. Strongly heated, it fuses, gives off oxygen gas, and leaves a white residue (potassium chloride), which readily dissolves in water, and produces a solution which yields a white precipitate (silver chloride) with silver nitrate, indicating the presence of chlorine, and a yellow precipitate (potassium-platinic chloride) with platinum chloride, showing the presence of potassium. It explodes when triturated in a mortar with sulphur. ... 

Silver chloride is an example of a soft crystal and is therefore not susceptible to the problems seen when precipitating hard crystals such as barium sulfate and calcium oxalate. This, however, does not mean that the opalescence obtained in a test or standard solution is independent of the operational parameters of the precipitation procedure. But it can be considered a more reproducible and rugged determination compared to hard crystal precipitations, and the steps in the procedure contributing to loss of reproducibility are more easily standardized. The most obvious difference is that a fairly reproducible test procedure can be obtained without the use of a seeded standard, as is the case in 6.3. Calcium and 6.12. Sulfates. 

Potassium acid oxalate Potassium alum dodecahydrate Potassium bromide Potassium carbonate Potassium manganate Potassium perchlorate Potassium permanganate Potassium persulfate Potassium thiocyanate PVP Pyrogallol Quinone Resorcinol Silver Silver chloride... 

Bergman found that silver and mercurous oxalates blacken in sunlight. Scheele found that metallic silver is formed in silver chloride blackened by light, and that it grows black sooner in the violet than in any of the other rays , the first distinction of the different chemical effects of light of different colours. He seems to have known of Schulze s work. ... 

Draper built a light concentrator based on a convex lens that had been prepared in such a way that the focal point remained the same during all of the sun progress in the sky. The sample was placed in that point and irradiated. Considerable heath was evolved, as shown by the melting of various substances, including silver chloride. In chlorine water, water was consumed much faster than it was by exposure to non-concentrated light, and iron oxide oxalate evolved carbon dioxide and led to a precipitate of the Fe(ll) oxalate, likewise at a much enhanced rate. 

Dioxane solutions of mercuric iodide react also with Ag+ and Au+ ions. If the quantity of palladium is not too small, these interferences can be avoided by throwing down silver chloride, or by precipitating metallic gold with oxalic acid, before making the test for palladium. Platinum salts do not react with mercuric iodide. 

Electrodes of the second type have been made with various insoluble halides (silver chloride, silver bromide, silver iodide and mercurous chloride) and also with insoluble sulphates, oxalates, etc. 

The method may be applied to those anions (e.g. chloride, bromide, and iodide) which are completely precipitated by silver and are sparingly soluble in dilute nitric acid. Excess of standard silver nitrate solution is added to the solution containing free nitric acid, and the residual silver nitrate solution is titrated with standard thiocyanate solution. This is sometimes termed the residual process. Anions whose silver salts are slightly soluble in water, but which are soluble in nitric acid, such as phosphate, arsenate, chromate, sulphide, and oxalate, may be precipitated in neutral solution with an excess of standard silver nitrate solution. The precipitate is filtered off, thoroughly washed, dissolved in dilute nitric acid, and the silver titrated with thiocyanate solution. Alternatively, the residual silver nitrate in the filtrate from the precipitation may be determined with thiocyanate solution after acidification with dilute nitric acid. 

Oxalate of lime is a white powder, formed whenever oxalic acid, or one of its soluble salts, is added to a calcareous solution. It is also found in a crystallized state in animal and vegetal tissues. It is insoluble in water, solution of chloride of ammonia, or acetic acid, hut dissolves readily in dilute nitric or hydrochlorio acid, and is decomposed on prolonged boiling with soluble salts of load, copper, silver, cadmium, zinc, nickel, cobalt, strontia, or baryta. 

Oxidation processes involving the subsequent titration of an excess of ferrous sulphate,2 oxalic acid (in the presence of silver sulphate as catalyst), titanous chloride,4 or of the quantity of iodine liberated from potassium iodide,5 are also available but are less satisfactory. In the last-named method a large excess of potassium iodide is necessary to obtain complete reaction in a short time. The reaction may be accelerated by the addition of potassium chloride6 or ammonium chloride with 20 per cent, by weight of the latter salt present a large excess of the iodide is not necessary and the liberated iodine may be titrated after fifteen minutes.7... 

Chlorides. — Dissolve 5 gm. of oxalic acid in 50 cc. of water, add 15 cc. of nitric acid and a few drops of silver nitrate solution. The solution may exhibit at most a slight opalescent turbidity. 

The tests for arsenic, heavy metals, chlorides, substances which reduce ammoniacal silver nitrate, free acids and bases, oxalic, sulphuric and fatty acids, and inorganic matter, are to be made in the manner described under Glycerin, sp. gr. 1.250. 

Alkaline Earths Chlorides. lit) ee.. of the 1 20 aqueous solid ion should he nlTcofcd neither by ammonium oxalate Solid inn nor hy silver nitride solution. 

Calcium Chlorides. —20 cc. of the 1 20 aqueous solution prepared by the aid of heat should not be affected by ammonium oxalate solution and it should develop at most a slight opalescence on the addition of silver nitrate solution. 

Chlorides, Heavy Metals (Fe, Cu), Calcium, and Magne-siuinl. 20 cc. portif iis of (In 1 lit) aqueous solution should not be alTeclcd hy hydrogen sulphide water, nor hy numio-uinin oxalate, silver nitrate, and sodium phosphate solutions. 

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