Fusion test for

In order to ascertain whether sufficient nickel to complete a given reaction has been used, the liquid phase may be tested for starting material before an attempt is made to isolate a product. In general the sodium fusion test for sulfur is satisfactory for this purpose but in certain individual cases a specific test may be more convenient. Thus, in the desulfurization of thioacetals (mercaptals), unreacted material... 

The Beilstein or the sodium fusion test for the presence of halogen. 

Sulphur. THE LASSAIGNE SODIUM TEST. The sodium fusion will have converted any sulphur present in the original compounds to sodium sulphide. Dissolve a few crystals of sodium nitroprusside, Na8[Fe(CN)5NO],zH20, in water, and add the solution to the third portion of the filtrate obtained from the sodium fusion. A brilliant purple coloration (resembling permanganate) indicates sulphur the coloration slowly fades on standing. Note, (i) Sodium nitroprusside is unstable in aqueous solution and therefore the solution should be freshly prepared on each occasion, (ii) This is a very delicate test for sulphides, and it is essential therefore that all apparatus, particularly test-tubes, should be quite clean. 

This solution may also be employed in the test for bromine. If iodine has been found, add small amounts of sodium nitrite solution, warm shghtly and shake with fresh 1 ml. portions of carbon tetrachloride until the last extract is colourless boil the acid solution until no more nitrous fumes are evolved and cool. If iodine is absent, use 1 ml. of the fusion solution which has been strongly acidified with glacial acetic acid. Add a small amount of lead dioxide, place a strip of fluorescein paper across the mouth of the tube, and warm the solution. If bromine is present, it will colour the test paper rose-pink (eosin). 

Alternatively, add 1 or 2 drops of 5 per cent, nickel nitrate solution to 2-3 ml. of the fusion solution, filter off the nickel cyanide and/or nickel sulphide, acidify the filtrate with 2N nitric acid, and test for hahdes as above. 

Hexane is readily distinguished from the other three compounds because there is a negative test for Cl after Na fusion and treatment with acidic AgNO,. The remaining three compounds are differentiated by their... 

Colorimetric Tests for Explosives, Propellants and Pyrotechnic Compositions. These tests include determinations of beat of combus ioa(designated as Q ), beat of explosion(Q ), beat of formation(Qt), beat of fusion... 

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