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Home > (1.1 1b.) water, and of...
Previous Next The best candle and soap tips online! (1.1 1b.) water, and of this liquid used for 20 cr.bic centimetres (5.40 fl.uidrachn:s) normal nitric acid 18 cubic centimetres (4.86 fluidrachms), then in case the first mixture contained 500 cubic centimetres (16,9 fl. ozs.) we should have to add to this 5o.oo cubic centimetres (1.87 fl. oz.) distilled water hi order to obtain an ammonia liquid which is equivalent to the normal nitric acid. The testing of potash is performed in the alkalimetric way. An average sample mixed from the contents of an entire cask is weighed oft', 10 grammes (0.85 oz.) are dissolved in a graduated flask of 100 cubic centimetres (3.S8 fl. ozs.), and left ta settle until clear, when 10 cubic centimetres (2.7 fluidrachms) are taken therefrom for titration with nitric acid, adding some litmus tincture and then warmed. Since 10 cubic centimetres of nitric acid correspond to 0.6911 gramme of pure carbonate of potash, the grammes of carbonate of potash which are contained in the 10 cubic centimetres are found by multiplication, when the used cubic centimetres of nitric acid are multiplied with the fig-ire 0.6911 and the product is divided by 10. For example, 10 cubic centimetres solution of potash = 1 gramme (15.44 grains) potash have required 8.5 cubic centimetres (2.29 fluidrachms) nitric acid 8.5 x 0.6911 = 5.8743: 10x0.58748=58.743 grammes or per cent, of pure carbonate of potash. This calculation is avoided if in Y\en of 10 grammes (0.35 oz.), 6.911 grammes (106.6 graine) potash are weighed, otherwise, however, proceeding in the described manner; instead of nitric acid a solution of oxalic acid may be used, for which purpose the oxalic acid which is found in commerce is amply sufficient. ESTIMATOR OF THE AMOUNT OF SODA IN LYES OF POTASH. For this we require, besides the normal nitric acid and the tincture of litmus, the following substances: 1. Chloride of barium; 2. Nitrate of silver; 3. Carbonated oxide of silver; 4. Solution of neutral chromate of potassa; the latter to serve as a standard. These preparations can be purchased of any druggist. From the nitrate of silver is made a solution 186 TECHNICAL TREATISE ON SOAP AND CANDIES. ALKALIMETRY. 187 of 17 grammes (0.59 oz ) to 1 litre (1.56 quarts), which serves as normal titre. 6.90 grammes (106 grains) potash are dissolved in a little water, and the solution not being clear filtered, and the residue washed out with so much distilled water that 100 cubic centimetres (3.38 fl. ozs.) liquid are produced, the residuum ia dried, calcined, and weighed. Its weight is QMS gramme (1.05 grain). Of the filtered substance 10 cubic centimetres (2.70 fl. drros.) were titrated with standard nitric acid, and thereby the value of alkali (soda and potash, if the first was present) and the carbonic acid ascertained. There were 8.99 cubic centimetres (2.42 fl. drms.) nitric acid, in all therefore 89.9 cubic centimeters (3 fl. ozs.) standard nitric acid used, which correspond to 1.977 carbonic acid. Then we again take 10 cubic centimetres (2.70 fl. drms.) of the potash solution, diluting the same with 20 to 30 cubic centimetres (0.67 to 1.01 fl. oz.) water, neutralising it with diluted chemically pare nitric acid, adding a few drops of chromate of potassa, and titrate with nitrate of silver until the first white precipitate attains a weak reddish color, which it retains. In all there are 5 cubic centimetres (1.35 fl. dnn.)t consequently 50 cubic centimetres (1,69 fl. oz.) solution of silver used, since 1000 cubic eeutimetres (1.067 qta.) thereof, with 3.5 grammes (54 grains) of chloride, correspond, there are consequently in 6.9 grammes (106 grains) potash 0.175 grammes (2.70 grains) chloride of potash. An additional 10 cubic centimetres (2,70 fl, drms.) are to be neutralized by nitric acid, diluted in water, and mixed with chloride of larium. In lieu of the sulphates of potash or soda, then present, an equivalent quantity of chloride of potash or chloride of soda, besides a little surplus of chloride of barium, ia produced hereby. The sulphate of barium is separated, completely washed oit, and the liquid mixed with a sufficient quantky of nitrate of silver. Hereby all the chlorides are changed itito carbonates, of which the carbonate of barium is not soluble and precipitates to the bottom, and is separated by filtration and washing out. The liquid now contains the chloride of tlie alkali (as originally contained in the potash) as also the carbonated alkali, formed by the chloride of potassium and chloride of sodium, calculated aa carbonia acid. Only the latter comes into consideration in our analysis, and we must therefore, after having fixed by titration with standard nitric acid the total amount of it, or rather of the carbonate, now deduct that quantity which belongs to the original contents of the potash. Supposing now, through the carbonated oxide of silver, there had been found in 10 cubic centimetres (2.70 fl. drms.) of the solution of potash, 0.022 gramme (0.34 grain) in all, hence 0.22 gramme (3-30 grains) carbonate, which are equivalent to 0.355 gramme (5.48 grains) chloride. Here, from the above 0.17.5 gramme (2.70 grains), chloride must be deducted, and we obtain then 0.180 gramme (2.77 grains) chloride, corre-ponding to 0.1118 gramme (1.72 grain) carbonate, aa an equivalent for the sulphuric acid which had been present But 0.22 gramme (3.40 grains) carbonate are equal to O.-tO gramme (ti.17 grains) sulphuric acid, thence correspond to 0.1118 gramme (1.72 grain) carbonic acid, 0.2032 gramme (3.14 grains) sulphuric acid. In 6.90 grammes (10G grains) of the potash are therefore found:— Carbonic acid . 1.977 grammes (30.50 grains) Chloric " - 0.175 " ( 2.70 » ) Sulphuric « . 0.2032 " ( 8.14 " ) According to the experiments of Gruneberg, sulphuric an,d hydrochloric acida always abound in potash. Calculating accordingly from the quantity found the chloride of potash and the sulphate of potash present, we obtain for the former— 0.3685 gramme ( 5.68 grs.), and for the latter: 0.3757 " ( 5.79*** ) 0.7442 " (11.47 " ), these with the undissolved residue 0.0380 " ( 1.04 « ) 0.8122 " (12 51 " ) of the applied 6.90 grammes (106 188 Previous Next
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