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Elements of chemistry, including the actual state and prevalent doctrines of the science / By the late Edward Turner.

  • Turner, Edward, 1798-1837.
Date:
1847
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry, including the actual state and prevalent doctrines of the science / By the late Edward Turner. Source: Wellcome Collection.

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    URIC ACID AND THE METALLIC OXIDES. 781 acid may be recognized. Fused with hydrate of potassa, carbonic acid, and cyanate of potassa, and cyanide of potassium are obtained ; boiled with peroxide of lead in water, it is decomposed into allantoine and oxalic acid, and urea is separated. Is insoluble in ether and alco¬ hol. With sulphuric acid it forms a crystalline compound. (Fritzsche.) • Its empirical formula is C10N4H4O6, or 2U1 + (C2H4N202). The latter formula represents uric acid as a compound of urile or cyanoxalic acid with urea ; and there is every reason to believe that it contains urea ready formed. In addition to the evidence arising from the action of heat upon it, as well as from the products of its oxidation by peroxide of lead, as above described, Gregory has shewn that when uric acid is acted on by permanganate of potash, urea is found among the products. As urea is never formed by oxidation, and moreover, according to Gregory, resists the oxidizing agency of the permanganate, we can hardly avoid the conclusion that urea exists as such in uric acid. This would render the existence of the supposed radical urile or cyanoxalic acid, C8N204, or 2(C202 + Cy), almost a matter of certainty. The above formula is supposed by Liebig and Wohler to represent uric acid as a monobasic acid, C10N4H3O5,HO. But the recent re¬ searches of Bensch on this acid seem to shew that it is either C5N2H02,H0, or C10N4H2O4,2HO. Bensch considers the acid to be monobasic, adopting the halved formula ; but as, according to his researches, it has a very marked tendency to form acid salts and double salts, which is the character of a bibasic acid, it is not easy to see why he has not adopted the formula C10N4H2O4,2HO, and viewed the acid as bibasic. This view seems to agree with his results better than that which he prefers. URIC ACID AND THE METALLIC OXIDES. Uric acid, as above stated, has a great tendency to form acid salts. Bensch has described the neutral and acid urates of potash and soda, but the urates of ammonia, lime, baryta, strontia, and magnesia are only as yet known as acid salts. Now since acid salts of these bases, except ammonia, only occur in the case of polybasic acids, we prefer to consi¬ der uric acid as bibasic. The general formula for the neutral urates is, according to Bensch, C5N2H02,M0, or, on the bibasic hypothesis, C10N4H2O4,2MO. That for the acid salts is C5N2H02,M0 + C5N2H02,H0 (Bensch), or, on the other view, C10N4H2O4, All the urates are very sparingly soluble, but the neutral salts are rather (MO (HO