Course of qualitative chemical analysis / by the late Wm. Geo. Valentin.

  • Valentin, W. G
Date:
1880
Catalogue details

Licence: Public Domain Mark

Credit: Course of qualitative chemical analysis / by the late Wm. Geo. Valentin. Source: Wellcome Collection.

    73/290 (page 59)
    ■whicli mercury can be separated again by distillation, gold and silver being left behind. The combination of the metal mercury with other metals at the ordinary temperature is obviously due to its liquid condition, which facilitates its being brought into intimate or molecular contact with other metals. This contact action is materially increased, if the solid metals are offered to the mercury in a finely divided condition, or in the form of foil. An amalgam of 4 parts of tin and 1 part of mercury is employed for making looking- glasses. HgS (as well as SAgj, Au.Ss, PtSi) parts with its sulphur when roasted in the air, and yields the metal; it is in fact reduced to the metallic state by oxygen, owing to the weak affinity which exists between the metal mercury and the non-metal sulphur, and owing likewise to its weak affinity for oxygen, on account of which the HgO (and OAgj) first formed gives up its oxygen again to a fi’esh quantity of HgS (or SAgo). Hydrogen and carbon, copper, tin, zinc, etc., reduce HgS at a high temperature, forming with the sulphur SHj, CS2 (carbon disulphide), CuS, etc. The native HgS is, however, best reduced by the action of strong bases, such as lime or soda. Mix a little cinnabar with dry CONaoj, and heat in a little tube, sealed up at one end, or blown into a small bulb. Metallic mercury sublimes and forms a mirror in the cold part of the tube; the sulphur is fixed by the alkali metal. Mercury salts, when heated by themselves, out of contact with the £iir, volHtilize or suUlimc, Githor wittLOiiti dGCompositiori, sucJi as HgBr,„ HgCl 2) Hg,,Cl2 (without undergoing previous fu.sion), Hgl2,HgS; or they are decomposed into oxide or metal. Salts of mercury with fixed acids (PoOe, CrOa, etc.), leave fixed residues of acid or oxide (Cr203). REACTIONS IN THE WET WAT. Mercury foiuns two series of salts : mercurous ami mercuric salts. It dissolves readily in nitric acid, even in the cold, forming mer- curous nitrate, if the mercury be in excess, and mercuric nitrate, if the acid be in excess. These salts have the composition— n Mercurous nitrate. and Mercuric nitrate. Mercurous salts contain Hg-H ; mercuric salts, HgO. Mercurous oxide. Mercuric oxide. The oxygen atom being in the one case linked to two atoms of the dyad mercury, thus, | ^g^O, the mercury atoms being held together by one of their bonds, as well as by the bonds of the oxygen atom; in the other to one atom, thus Hg=0. Mercurous oxide exhibits a tendency to combine with another