Analytical reagents : standards and tests / compiled by Edmund White.

Date:
1911
Catalogue details

Licence: In copyright

Credit: Analytical reagents : standards and tests / compiled by Edmund White. Source: Wellcome Collection.

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    Residue: 1 Gm. boiled with 10 mils nitric acid and 10 mils of water should dissolve slowly and leave no residue. Sulphates: Take half the solution in the preceding test, evaporate until no more nitrous fumes are evolved, dilute to 100 mils and add 2 mils barium chloride solution; only the faintest opalescence should be produced after standing five minutes. Trade Varieties. For commercial purposes phosphorus is sold in thick sticks and in slabs, which frequently contain particles of foreign matter but otherwise are of fair purity. PLATINUM PERCHLORIDE. PtCl4,2HCl,6H20. Reddish-brown crystalline masses, very deliquescent. Tests. Solubility: A 5 per cent, solution in water should be per- fectly clear and pale yellow. Iridium: The presence of this impurity is shown by the aqueous solution having a brownish tinge. Residue: 1 Gm. carefully ignited in a porcelain crucible should leave a residue of spongy platinum weighing not less than 037 Gm. This residue when extracted with water should yield less than 2 Mgm. soluble solid residue. Trade Varieties. These may be incompletely soluble in water or alcohol, and when prepared from platinum scrap frequently form a brown solution, due to the presence of traces of iridium. POTASSIUM ACETATE. kc2h3o2. White granular crystalline powder, or masses; very de- liquescent. Melts a little below 300° C. Tests. Solubility: Soluble in about half its weight of water and 2 parts of alcohol. The aqueous solution is alkaline to litmus. Sulphates : 1 Gm. with 20 mils o,f water and 2 mils hydro- chloric acid should show no turbidity on the addition of 1 mil barium chloride solution after setting aside half an hour. Chlorides : 1 Gm. with 30 mils of water and 2 mils nitric acid should show no immediate turbidity on the addition of 1 mil silver nitrate solution, and only the faintest opalescence on standing half an hour