Chloride of Ammonium

Mr. Alexander Ckoll has taken out a patent for freeing gas from its ammonia, and a part of the sulphide of hydrogen, producing at the same time chloride of ammonium. He introduces a solution of the chloride of zinc into a vessel, upon the same construction as a wet lime purifier on admitting the gas, double decomposition ensues an insoluble sulphide of zinc, and a solution of chloride of ammonium, aro produced. The gas must be further purified with lime in the usual way. 

There are, however, certain chemical reactions by which platinum may be readily distinguished and separated from the gold in solution. Sulphate of iron and oxalic acid, which precipitate gold, do not precipitate platinum. When the latter is dissolved in aqua regia, and the acid neutralized by carbonate of soda, it is deposited as a black powder, if the mixture be boiled with tartaric acid and sodar—the ingredients of a Seid-litz powder. Further, the addition of chloride of ammonium and alcohol te a strong solution of platinum, causes the deposition of a yellow crystalline precipitate, which is charactsristtc of this metal. These and other reactions may be summarily stated as follows... 

It is evident that other methods end reagents may be adopted. For example, the original solution In aqua regia may be concentrated by evaporation, until it is very much reduced in quentlty then add about throe-fourths of its bulk of spirit of wine, and, lastly, a saturated solution of chloride of ammonium. By these reagents the platinum will be thrown down as a yellow Crystalline precipitate, while the solution filtered from this, and treated with sulphate of iron or boiled with oxalic acid, deposits geld. 

Braude states, that the salts of magnesia are mostly soluble in water, and bitter they are all soluble in hydrochloric acid their aqueous solutions are precipitated by potassa and soda, the precipitate, being soluble In hydrochloric, nitric, and sulphuric acids, and in hydroohlorate, nitrate, and sulphate of ammonia. Ammonia only throws down part of the magnesia, and forms a double salt, and carbonates of potassa and soda only throw down part of the magnesia, except the solution be hentad, when pearly the whole is precipitated. Chloride of ammonium redissolves tiro deposit, and when previously added to the magnesian solution, no precipitate ensues on adding the alkaline carbonates, unless the liquor be warmed The bicarbonates of von. ir. 

For Ammonia.—If the sample is rich in ammonia, about twenty grains, and, if poor, about fifty grains are taken, a few drops of hydrochloric add added to prevent the loss of this alkali, which takes place in some guanos on exsiccation, and then dried at 212°, and burnt with soda-lime, which must also be previously desiccated and cooled immediately before use. The mixture is introduced as rapidly as possible into tbe combustion tube. No appreciable loss of ammonia occurs if the substsnccs are well dried before mixing, For ordinary purposes, sufficiently exact results are obtained by simply evaporating the chloride of ammonium on a water hath to dryness. One part of this salt represents 0 315 of ammonia,... 

To estimate as pyrophosphate of magnesia, a weighed portion is taken, and treated with nitrie acid until entirely dissolved. The solution is mixed with a considerable exoess of ammonia chloride of ammonium is then added and lastly, sulphate of magnesia, as long as a procipitete continues to be formed. The mixture is allowed to stand twelve hours the deposit of phosphate of magnesia and ammonia is then collected by filtration, and well washed with dilute solution of ammonia, dried, and heated to intense redness, to expel all traces of ammonia. Every one hundred parts of pyrophosphate are equal to 28 16 of phosphorus. 

Wollaston s method, of which the preceding is a modification, is the most perfect, and that best calculated to yield a pure metal,. Vauquelin struck upon the same, but in its details that of the former is the most complete. For tire preparation of the pure metal, the platiniferous grains arc treated with aqua regia and chloride of ammonium, as in the preceding case ouly, to prevent the solution of the iridium it is necessary to dilute the acids, so that it will remain in the residue. It is well to reduce the strength of the- hydrochloric acid with on equal quantity of water, and also that the aqua-fortis and muriatic acid bo quite pure. - Wollaston has indicated that a quantity of ydrochlorio acid, equivalent to one hundred and fifty of dry acid, and as much nitric acid as will contein forty parts, Is sufficient for the solution of a hundred parts of the platiniferous matter hut as it is best to have an excess of the ore, one hundred and twenty parts of the latter should be employed. The action of the compound acid should... 

One of the most economical of these processes is that proposed hy Messrs. Hemming and Dyer, which is founded on the behavior of a solution of common salt with one of bicarbonate of ammonia. When carbonate of ammonia of commerce, which is in reality a mixture of carbonate and bicarbonate, is added in a etate of lino powder to a solution of about an equal weight of salt in throe parts of water, tho mixture being well stirred, a white crystalline precipitate appears in a few hours, causing the liquid to become thick. This precipitate is bicarbonate of soda, and there is contained in solution chloride of ammonium, produoed as shown in the annexed equation-... 

Under salts, el cetera, are included malic acid and gum, nitrogenous "subatanoes, fatty matters, aromatic substances, coloring matters, essential oil, chlorophyle, malamide, oxalate and phosphate of lime, phosphata of magnesia, chloride of, ammonium, silicate, nitrate, sulphate, and oxalate of potassa oxalate of soda, chlorides of sodium and potassium, peetates and pectinates of... 

Protoxide of Manganese—MnO—may be economically prepared by beating chloride of manganeso to redness with twice its weight of carbonate of soda and a little chloride of. ammonium, exhausting the fused mass with water when cold the residuum is protoxide of manganese. 

He suggested that two hydrogen atoms, one from each ammonia molecule, were displaced by the copper atom, and he viewed the salt as a chloride of cuprammonium similar to the chloride of ammonium , thus explaining the strong retention of the ammonia in the compound. Graham s theory... 

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