NITRO1]YDROCHLOR1C ACID. AitromurfoticAcid. Aquallegia. A powerfully corrosive liquid, formed on mixing one measure of nitric acid with about three of hydrochloric acid. The alchemists called it aqua regia, from its property of dissolving gold, their " king of metals." It also attacks and dissolves platinum, and of course exerts the same action on all those metals that are soluble in nitric acid or hydrochloric acid separately ; perchlorides in all cases being formed.
The solvent action of nitrohydrochloric acid has been shown by M. Gay-Lussac to be due to free chlorine. At least two other bodies sre, however, produced simultaneously with the chlorine ; they are rich in chlorine, but do not act upon metals; the one is chloronitric gas, the other chloronitrous gas.
Chloro-nitric Gus. (NO, Cl,). This gas constitutes the yellowish-red fumes that arc evolved when nitrohydrochloric acid is gently heated. Passed through a tube surrounded by a freezing mixture it condenses to a cloudy lemon-coloured liquid. Its formation is attended with
evolution of chlorine, as indicated by the following equation:— Cldoro-nitric gas is decomposed by water, chlorine and peroxide of nitrogen remaining in solution. It readily acts upon mercury but is not an acid, and does not combine with bases. It may be viewed as peroxide of nitrogen in which two equivalents of oxygen are replaced by two of chlorine.
Chloro-nitrons pea. (NO,CI). This gas conies off in greatest abund ance towards the latter part of the operation of boiling nitro-hydro chloric acid. It may also be obtained directly by allowing binoxide of nitrogen and chlorine to condense together in a vessel surrounded by a freezing mixture. Like chloronitric gas it is decomposed by water, and though not itself an acid may be viewed as nitrous acid in which an equivalent of oxygen is replaced by one of chlorine.