1821.] Action of Chlorides and Water. 29 



decomposition, or being changed into hydrochlorates during 

 that solution." He further states, ^* I admit as a principle that 

 we ought to have a chloruret or a hydrochlorate in solution, 

 according to the forces which act in order to decompose water 

 are greater or less than those which keep its elements united." 



In atteAipting to elucidate this as well as every other subject, 

 it will be better to begin with those cases which are too obvious 

 to admit of question, and proceed to those which are more 

 obscure. There are some cases of the action of water upon 

 chlorides which prove, I think, incontestably the decomposition 

 of the water, and the union of its oxygen with the metal, and 

 its hydrogen with the chlorine — I mean the effects observed 

 when the chloride of bismuth and of antimony are acted upon. 

 It is quite evident that oxides of these metals are precipitated,, 

 and that muriatic acid remains in solution. It will be unques- 

 tionably admitted, whether we dissolve a metaUic oxide in 

 muriatic acid, or take the dry compound which remains after 

 evaporating such solution, and exposing it to a red heat, and 

 dissolve it in water, that the solutions obtained are in all respects 

 similar. Thus when we dissolve peroxide of iron in muriatic 

 acid, we obtain a red coloured solution ; and a similar effect is 

 produced, if we dissolve the perchloride of iron in water., 

 both solutions it will be admitted contain either chlorides or 

 muriates. 



When iron is put into dilute muriatic acid, it is well known 

 that hydrogen gas is evolved, and the iron dissolved. Now if we 

 conceive this solution to contain chloride of iron, w^e must sup- 

 pose that the hydrogen evolved is derived from the decomposi- 

 tion of the muriatic acid, and not of the water ; and as w^e obtain 

 a similar solution by dissolving protoxide of iron in muriatic 

 acid, we must suppose thSit the oxygen of the oxide unites with 

 the hydrogen of the muriate acid, that water is formed, and 

 chloride of iron remains in solution. I say we must admit the 

 evolution of hydrogen from the decomposition of the muriatic 

 acid in the first case, or we must make the improbable suppoi- 

 sition that iron, while dissolving, decomposes water to receive 

 oxygen from hydrogen, and that immediately afterwards it 

 yields the oxygen to the hydrogen of the muriatic acid, and thus 

 produces chloride of iron. 



From these considerations, I think it will involve fewer diffi- 

 culties to consider this solution as containing a muriate rather 

 than a chloride. We have in this case only to admit, as is 

 indeed generally allowed, that the hydrogen is evolved from the 

 decomposition of the water, and not of the acid ; and when the 

 oxide of iron is dissolved in hquid muriatic acid, we must con- 

 sider that the oxygen of the oxide and the hydrogen of the acid 

 do not form water, but remain combined, the first with the iron, 

 :and the hydrogen with the chlorine. 



