Proceedings of the Royal Society of London/Volume 2/On the Action of Acids on the Salts usually called Hyperoxymuriates, and on the Gases produced from them

From Wikisource
Jump to navigation Jump to search

On the Action of Acids on the Salts usually called Hyperoxymuriates, and on the Gases produced from them.By Sir Humphry Davy, LL.D. F.R.S.Read May 4, 1815.[Phil. Trans. 1815, p. 214.]

M. Gay-Lussac having obtained, by the action of sulphuric acid on hyperoxymuriate of barytes, a peculiar compound, to which he gave the name of chloric acid, the author was induced to examine the action of this and other acids on the hyperoxymuriate of potash, and after various attempts, found the following process with sulphuric acid to be the best. A small quantity, not exceeding fifty or sixty grains, of the hyperoxymuriate are to be mixed with a small quantity of the acid in its concentrated state, and to be rubbed together by means of a spatula of platina till incorporated into a solid mass of a bright orange colour. This mass having been introduced into a small retort, is to be then warmed by immersion in water gradually heated, but kept below the boiling point. As the heat rises, an elastic fluid is emitted of a bright yellowish green colour. This gas may be received over mercury, on which it has no action; but it is rapidly absorbed by water. Its smell is aromatic, without any smell of chlorine. It destroys vegetable blues, without previously reddening them. By a temperature of 212° it explodes with more violence than euchlorine, expanding more, and producing more light. After the explosion the volume is found increased in the proportion of 2 to 3; two parts of the product being oxygen, and the remainder chlorine.

Phosphorus introduced into this gas occasions an explosion, and burns in the liberated gases with its usual brilliancy; but other combustible bodies have no action on the gas.

Water saturated with the gas is of a deep yellow colour; it does not taste sour, but astringent and corrosive, leaving a lasting and disagreeable impression on the tongue.

It appears to the author not impossible, that the gas to which he formerly gave the name of euchlorine, may be a mixture of the new gas with chlorine; and indeed the action of water upon euchlorine favours this idea, since it acquires the same colour from it, and leaves a residuum of chlorine; but, on the contrary, the circumstance that Dutch foil has no action upon euchlorine, seems to show that it contains no free chlorine merely intermixed, but that the whole is chemically combined.

The saturated solution of the new gas in water, when mixed with alkaline solutions, does not immediately lose its colour, or neutralize the alkalies, but after a time the hyperoxymuriates are formed, and the colour disappears.

In consequence of the doubt which now occurs concerning the true nature of euchlorine, the author declines giving a name to the present compound, till he can have an opportunity of making some new experiments on that subject.