The Pharmaceutical era . furous acid gradually com-bines with oxygen to form sulfuric acid, so that nearlyall of its solutions contain more or less of the latter com-pound. The salts of sulfurous acid, the sulfites, are an impor-tant class of compounds, useful both in the arts and inmedicine, their chief value lying in their ability to re-lease sulfur dioxid when treated with an acid. This re-action also serves to detect them in the process of analy-sis. —This is a colorless, heavy, oily liquidformerly called nil nf vitriol, because first obtained bythe distillation of green
The Pharmaceutical era . furous acid gradually com-bines with oxygen to form sulfuric acid, so that nearlyall of its solutions contain more or less of the latter com-pound. The salts of sulfurous acid, the sulfites, are an impor-tant class of compounds, useful both in the arts and inmedicine, their chief value lying in their ability to re-lease sulfur dioxid when treated with an acid. This re-action also serves to detect them in the process of analy-sis. —This is a colorless, heavy, oily liquidformerly called nil nf vitriol, because first obtained bythe distillation of green vitriol. TheArldum Sulpltrnicuin of the Pharmacopoeia con-tains per cent, of the absolute acid, and has a spe-cific gravity of It can be preparetl like sulfurousacid, by dissolving the corresponding anhydrid in , + II,0 -^ H, On the commercial scale it is manufactured by jtassinf;into large leaden chamlxrs. sulfur dioxid, obtained byburning sulfur, sleani, air, and nitric acid, or certain ox-. ids lit iiilri);;iu. iFii;. - > Ihi- sulfur dioxid cannotreadily take up oxygen from the air, but can easily take November IS, 1897.] THE PHARMACEUTICAL ERA. 751 it from the nitric acid or the nitrogen oxids which arepresent. The latter in turn take up fresh oxygen fromthe air, and thus act as carriers of oxygen from the airto the sulfur. The completed reaction may be represent-ed by the following equation, though it is quite certainthat intermediate reactions occur: 3H,S03 + 2HXO, = 3H,S0, + 2XO + The weak acid of the chambers is first concentrated inleaden and then in platinum !, and finally purifiedby distillation from platinum stills. Sulfuric acid is probably the most important acidknown. It is used in the preparation of many otheracids, and in a large number of other chemical opera-tions. Enormous quantities of it are consumed yearly. The concentrated acid has a great aflinity for water,mixing with it with the evolution of considerable he
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Keywords: ., bookcentury1800, booksubjectdrugs, booksubjectpharmacy, bookyear1
