34 



Proportions 

 requited* 



The experi- 

 ments repeat- 

 ed , 



Sotla tlius pre- 

 pared therefore 

 noi le^l alkali. 



Ixpcriinents 

 repeated witli 



purlSeJ wUll 

 iMil without 



ON THE PURITY OF THE FIXFD ALKALIS. 



none of these specimens were pei Teclly pure ; all of them 

 indicating blight traces of tnuriutio acid, and a greater or 

 less proportion of cavbonic acid, easily detected by barytic 

 salts, barytes water, lime water, &c., but too little for a 

 solution not very strong to efl'ervesce on the addition of the 

 acid. On neutralizing 20 gr. [309 gi"«] of each of these 

 specimens, I found, that 100 parts of 



N° 1 had absorbed HO'2 of concentrated sulphuric acid, 



•2 116-75 



3 111-5 



4 112-2 



This would indicate, takii)g the mean of the vomits, th»t 

 100 parts of caustic soda required only 112-G6'2 of concen- 

 trated sulphuric acid for their neutralization. 



Apprehending, that the specimens of soda employed, 

 notwithstanding they had been in fusion, might contain 

 more or less water, I repeated these experiments on similar 

 portions of soda, which had been fused separately in a silver 

 crucible, and kept in this state at a red heat for twenty 

 minutes : but the proportions obtained differed so little frorfl 

 those above given, that it is unnecessary to insert them. 



On comparing these results with those before obtained, 

 we must conclude, that, if 20-35 of pure soda, in the sub- 

 carbonate analysed, required 34*7 of concentrated acid to 

 saturate them, 100 would take 170*515 : but we have just 

 seen, that 112'C62 of this acid were suflicient to neutralize 

 100 of the caustic soda prepared with alcohol; whence it 

 follows, that this soda was not pure, which is probable; or 

 that the analysis of the subcarbouate was erroneous, a sup- 

 position that I conceive inadmissible, from the various trials 

 made. 



Notwithstanding I was fcatihfi^d, that tne four specimens 

 of soda prepared with alcohol contained too smiiU a portion 

 of any known foreign matti-r, to occasion so great a dif- 

 ference between the results obtained, I thought it proper to 

 repeat the same esperimeats with |)ure soda prepared in a 

 different way. ' 



I took a kilogromme [3o]- vz avoird.] of perfectly pure 

 rr\ 4;jl!"/r,( ^Ti 1 1 )! pi t (> (\f souii : decouipused it bj' means of 



barytes. 



