Licence: Public Domain Mark
Credit: Qualitative chemical analysis / by C. Remigius Fresenius. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![9G STEONTIA. 3. Siilphuric acid and sulphates throw down sulphate of strontia, SrO.SO, [SrSOJ in the form of a white precipitate. Thrown down by dilute sulphuric acid from concentrated solutions, the sulphate- is at first flocculent and amorphous, afterwards pulverulent and crystal- line ; precipitated by dilute sulphuric acid from dilute solutions, or produced by solutions of sulphates, it is immediately pulverulent and crystalline. The application of heat gi-eatly promotes the precipitation. Sulphate of strontia is far more soluble in water than sulphate of baryta ; owing to this readier solubility, the precipitated sulphate of strontia does not separate from rather dilute solutions until some time has elapsed ; and this is invariably the case (even in concentrated solutions) if solution of sulphate of lime is used as the precipitant. Sulphate of strontia is insoluble in spirit of wine; the addition of alcohol, there- fore, will promote the separation of the precipitate. As sulphate of strontia dissolves perceptibly in hydrochloric acid and in nitric acid, the- presence of large quantities of these acids most seriously impair the delicacy of the reaction. If the solution of sulphate of strontia in hydro- chloric acid be diluted with water, it will be rendered turbid by chloride of barium. Sulphate of strontia does not dissolve when boiled with a concentrated solution of sulphate of ammonia. 4. Hydrofluosilicic acid does not produce a precipitate even in concentrated solutions; even when an equal volume of alcohol is added no precipitation takes place, unless the solution is concentrated. 5. Oxalate of ammonia, even from rather dikite solutions, throws down oxalate of strontia, 2SrO,Cp^ -f aq [2SrC.Oj,5H.O], in the form of a white precipitate which dissolves readily in hydrochloric and nitric acid, and perceptibly in salts of ammonia, but is only sparingly soluble in oxalic and acetic acids. 6. Bichromate of potassa does not precipitate solutions of salts of strontia, even when they are concentrated. Ifeutral chromate of potassa produces no precipitate at first; but on long standing, the bright yellow chromate of strontia separates in the crystalline form from neutral solutions, if not too dilute ; it is not formed if free acetic acid is present. The chromate is only slightly soluble in water, but readily in hydrochloric, nitric, and chromic acids. 7. If salts of strontia soluble in water or alcohol are heated with dilute spirit of wine, and the spirit is ignited, the flame appears of a very intense carmine colour, more particularly on stirring the alcoholic mixtuie. 8. If a strontia salt is held in the fusing zone of the Bunsen gas flame, or in the inner spirit blowpipe flame, an intensely red colour is imparted to the flame. With chloride of strontium, the re- action is the most distinct, less clear with strontia and carbonate of strontia, fainter still with sulphate of strontia, and scarcely at all with strontia salts of fixed acids. The sample, therefore, after its first ex- posure to the flame, should be moistened with hydrochloric acid, and then again placed in the flame. If sulj)hate of strontia is likely to be present, the sample is first exposed for a short time to the reducing flame- (to produce sulphide of strontium), before it is moistened with hydro- chloric acid. Viewed through the blue glass, the strontia flame appears purple or rose (difference between strontia and lime, the latter exhibiting a faint greenish-gray colour when treated in this manner); this reaction is best seen if the sample moistened vdth. hydrochloric acid](https://iiif.wellcomecollection.org/image/b21966953_0120.jp2/full/800%2C/0/default.jpg)
