Absorption of Nitric Oxide in Gas Analysis. 



By 



Edward Divers, M. D., D. Sc, F. R. S., Prof., 

 Imperial University, Tokyo. 



It is well known that the vapour tension of nitric oxide, 

 dissolved in the solution of a ferrous salt, interferes with the 

 use of this reagent to remove nitric oxide from other gases. 

 There is, however, another absorbent for nitric oxide which 

 leaves nothing to be desired, whose use and value have remained 

 unknown. This is a strong solution of either sodium or potas- 

 sium sulphite, to which a little alkali hydroxide is added. It 

 quickly absorbs every trace of nitric oxide, which it fixes in 

 the form of hyponitrososulphate, ^a.ß.DßO... I have already 

 made satisfactory use of it to analyse the mixture of nitric 

 oxide and nitrogen which is left on heating silver hyponitrite 

 and letting the solid and gaseous products cool in contact with 

 each other. The sulphite need not be very pure, the presence 

 of sulphate or carbonate being of no importance. If carbon 

 dioxide or other acid gas is present with the nitric oxide, it is 

 removed by alkali, before using the sulphite reagent. 



