Intelligence and Miscellaneous Articles, 157 



from the composition originally assigned to the chlorides of oxitles. 

 — LV;w//M Juillet 13, 1836. 



ON THE ACTION OF ANHYDROUS SULPHURIC ACID ON SOME 

 METALLIC CHLORIDES. 



M. Rose, in the course of his memoir, notices the researches of 

 L. Gmelin, which have shown tliat anhydrous sulphuric acid decom- 

 poses common salt in a very <lifterent manner to what the hydrated 

 acid does, for although the first converts it into sulphate of soda 

 like the second, yet in the first case the sodium is oxidized at the 

 expense of the sulphuric acid, and during the decomposition sul- 

 phurous acid is disengaged along with chlorine. M.L. Gmelin, and 

 after him MM. Sertiirner and Dobereiner, made all their experi- 

 ments by directingthe vapour ofanhydrous sulphuric acid upon heated 

 common salt. The result is, however, very different when the va- 

 ))our of the anhydrous acid is passed over chloride of sodium finely 

 powdered and placed in a vessel which is kept cool by a freezing 

 mixture. In this case the acid vapour is rapidly absorbed by the 

 metallic chloride without deconiposing it. The whole is converted 

 into a transparent mass, which is at firfct soft, but hardens by de- 

 grees ; it emits no fumes, not affording the slightest traces of hy- 

 drochloric acid, of chlorine, nor of sulphurous acid. This ma^s, 

 which is composed of anhydrous sulphuric acid and chloride of 

 sodium, deconiposes when heated, and is converted into sulj)hate of 

 soda, with the disengagement of chlorine and sulphurous acid g;is. 



The chloride of potassium and hydrochlorate of ammonia act in 

 the same manner with the vapour of anhydrous sulphuric acid as 

 common salt, except that the ammoniacal salt absorbs it with ever* 

 greater rapidity than the other two. U we heat the compound 

 formed by the salammoniac and the anhydrous acid, hydrochloric 

 acid gas is at first disengaged, and afterwards the phaenomena occur 

 which accompany the sublimation of sulphate of ammonia. 



If these compounds of anhydrous sulphuric acid and a chloride^ 

 are moistened with a few drops of water, abundance of hydrochloric 

 acid gas is immediately disengaged, and when also they are exposed 

 to a damp atmosphere they immediately begin to decompose, with 

 the evolution of tho same gas. 



All the metallic chlorides do not equally unite with anhydrous 

 sulphuric acid ; thus, it cannot be combined with the chlorides of 

 barium and copper in their anhydrous state. On the contrary, an- 

 hydrous sulphuric acid unites with some equally anhydrous salts ;. 

 a.nongst others, with the nitrate, and even, although slowly and with 

 difficulty, with tiie sulphate of pota»>h. The most important of these 

 compounds is that of anhydrous acid, with sulphate of ammonia, 

 likewise anhydrous, which is always simultaneously formed in the 

 preparation of these latter salts*, and which prevents us obtaining 

 them pure and in quantity. — Jour, de C/iimie Mcdicale, Oct., I8'i(i*. 



* So in the French. 



