This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1916 Excerpt: ... water bath for a few minutes, and filter into an evaporating dish. Evaporate filtrate and washings nearly to dryness, add 1 cc. of dilute H2S04 (1:1), evaporate to dryness, and ignite to whiteness. As all the potassium is in the form of sulphate, no loss need be apprehended by volatilization of potash, and a full red ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1916 Excerpt: ... water bath for a few minutes, and filter into an evaporating dish. Evaporate filtrate and washings nearly to dryness, add 1 cc. of dilute H2S04 (1:1), evaporate to dryness, and ignite to whiteness. As all the potassium is in the form of sulphate, no loss need be apprehended by volatilization of potash, and a full red heat must be maintained until the residue is perfectly white. Dissolve the residue in about 15 cc. of water, add a few drops of hydrochloric acid, and platinum solution (H2PtCl6) in slight excess (avoid the use of too large an excess, as the reagent is very expensive). Evaporate on a water bath to a thick paste, and treat the residue with 80 per cent alcohol (sp. gr. 0.8645). If enough platinum solution has been added to precipitate all the potassium, the alcoholic solution will be slightly colored. If the alcohol is not slightly colored, it must be evaporated off, the precipitate redissolved in water containing a few drops of HCl, more platinum solution added, and again evaporated to a thick paste and treated with alcohol as before. If the alcoholic solution is not colored, owing to an excess of platinum solution, do not add more platinum solution directly to the alcoholic solution, but evaporate off the alcohol first. Also avoid the absorption of ammonia by the solution. After the precipitate is treated with the 80 per cent alcohol, filter into a properly prepared and weighed Gooch crucible, wash thoroughly with 80 per cent alcohol, then with 10 cc. of the special ammonium chloride solution t to remove impurities. Repeat washing with the special ammonium chloride solution about five times, and Prepared according to directions on page 90. t Prepared according to directions on page 90. again wash thoroughly with 80 per cent alcohol. Dry the pr...
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