1892.] Formation and Decomposition of Nitrous Acid. 



53 



Series XXXVI. 



Temperature, 19'8. Nitrous acid = T1789 grams. Nitric acid = 

 0'3973 gram. Ratio of nitrous to nitric acid = 1 : O34. 



It follows, therefore, from the experiments the details of which 

 are given above, that solutions containing both nitrous and nitric 

 acids, whether prepared from silver nitrite and hydrochloric acid, or 

 from nitric oxide and nitric acid, or from nitrogen peroxide and 

 water, or from nitrous fumes and water, have this one property in 

 common, that the diminution of reducing material, presumably 

 nitrous acid, therein contained, proceeds in accordance with the same 

 law. The velocity of the change seems, however, to be dependent 

 rather upon the ratio of nitrous to nitric acid than upon the actual 

 masses of either of them. But though these solutions have this one 

 point in common, yet in other respects they differ most markedly. 

 For bubbles of gas, namely nitric oxide, are rapidly given off from 

 solutions prepared from nitrogen peroxide and nitrous fames, and to 

 a less degree from silver nitrite, though solutions from nitric oxide 

 and nitric acid do not give off bubbles of gas in a similar manner. 

 Again, all my former investigations* have shown that, whereas 

 metallic lead does not readily dissolve in solutions containing nitrous 

 acid, and prepared from silver nitrite, yet it dissolves very rapidly in 

 solutions equally containing nitrous acid, but prepared from nitrogen 

 peroxide and water. The cause for the similarity on the one hand, 

 and the dissimilarity on the other, must remain the subject of a fuller 

 enquiry. 



General Conclusions. 



The main points of this enquiry may briefly be summarised as 

 follows : 



* ' Soc. Chem. Industry Jl.,' 1891, p. 7.294. 



