Intelligence and Miscellaneous Articles, 237 



ON THE CHEMICAL AGENCY OF WATER. BY M. PELOUZE. 



Anhydrous alcohol, sulphuric aether and acetic aether, disguise, more 

 or less completely, the properties of the strongest acids. Their so- 

 lution does not redden litmus, nor decompose a great number of car- 

 bonates. A mixture of about 6 parts of absolute alcohol and 1 

 part of concentrated sulphuric acid does not act upon any neutral 

 carbonate, but it immediately decomposes acetate of potash, and dis- 

 engages abundant vapours of vinegar mixed with acetic aether. 



It is well known, since the labours of Hennell and Serullas, that 

 sulphovinic acid is formed in the cold, in a mixture of alcohol and 

 concentrated sulphuric acid, but whatever may be the excess of alcohol 

 employed, free sulphuric acid remains in the mixture. It is therefore 

 reasonable to conclude, from the above-mentioned experiment, that 

 an alcoholic solution of sulphovinic and sulphuric acid is incapable of 

 decomposing a carbonate ; water must be added that the action may 

 occur. 



A solution of muriatic acid gas in alcohol, so concentrated that 

 when diluted with several hundred times its volume of water it red- 

 dens litmus-paper, attacks artificial carbonate of lime and even marble 

 itself with extreme violence. It also attacks, but less strongly, the 

 carbonates of barytes, strontia, magnesia, and soda, even wheu they 

 have been previously calcined j but on the contrary it does not de- 

 compose carbonate of potash. Concentrated nitric acid mixed with 

 alcohol does not decompose carbonate of potash ; it acts energetically 

 upon the carbonates of lime and strontia j those of barytes, magnesia, 

 and soda are also attacked, but much more slowly. 



Vegetable acids produce similar effects ; the tartaric, paratartaric, 

 citric, and oxalic acids all dissolve in notable quantity in alcohol j 

 the solution of the two first did not act upon any of the numerous 

 carbonates with which it was put in contact. The alcoholic solution 

 of citric acid does not act upon the carbonates of strontia, lime, or 

 barytes, but it attacks the carbonates of potash and magnesia, but 

 the latter with extreme slowness. 



Oxalic acid, which disengages carbonic acid from the carbonates 

 of strontia, magnesia, and barytes, does not act at all upon carbonate 

 of potash or of lime. These facts show, that on many occasions in 

 which alcohol is employed in chemical investigations, it will prevent 

 the operator from discovering the presence of an excess of acid by 

 litmus-paper. 



M. Pelouze remarks that some of the facts cited may be satisfac- 

 torily explained, while others are quite inexplicable. What is the 

 reason, for example, why concentrated acetic acid does not act upon 

 carbonate of lime, while it combines so energetically with caustic 

 lime } Why is water required in the first case and useless in the second ? 

 — for in both cases the same product is obtained. Thus acetic acid 

 dissolved in alcohol, and acetic acid dissolved in water, may be con- 

 sidered, with relation to certain bodies, chalk for example, as acids 

 entirely distinct from each other. Acetic acid dissolved in alcohol is 

 to the carbonates, what carbonic acid is to the acetates dissolved in 



