OXIMIDOSULPHONATES OK SULPHAZOTA'l'KS. 47 



were used bv Freiny. In hot acid .solution oximidosulphoimtes are 

 converted into sulphates and oxides of nitrogen by oxidising agents, 

 such as nitric acid, bromine, and potassium chlorate, but the decom- 

 position is seldom so complete as to be available for determiniiig sul- 

 phur quantitatively. 



Action of stronfi snlfilmnc acid. — That strong sulphuric acid dis- 

 engages nitric oxide, as stated bv both Freniy and Claus, v^'e cannot 

 admit. Heated with this acid, a sodium or potassium salt dissolves and 

 evolves no gas luitil sulphuric-acid vapours are freely escaping, when 

 nitrous oxide and sulphur dioxide are slowly generated. Indeed, 

 addition of sulphuric acid should ])e made before igniting oximido- 

 sulphonates for analytical purposes, in order to avoid loss through 

 explosive decomposition. 



Behaviour iritli other salts in sohtion. — Disodium, dipotassium, or 

 diammonium oximid(i><ulj)honate does not precipitate other salts and 

 appears often not even to react with them, since on evaporation the 

 salts mixed together crystallise out unchanged. This interesting fact 

 was observed by Fremy in the case of the dipotassium salt mixed with 

 those of zinc, manganese, copper, and silver. Claus denied its truth. 

 We have fully verified it in the case of the disodium salt and copper 

 sulphate. These salts in about equivalent quantities were dissolved in 

 water and the solution made slightly turbid with copper hydroxide by 

 adding a minute quantity of sodium hydroxide, in order to guard 

 against hydrolysis supervening. By spontaneous evaporation copper 

 sulphate first crystallised out and then the sodium oximidosulphonate, 

 that is, in the order of their solubilities. This behaviour of the alkali 

 oximidosulphonates serves to show that as sulphonates they have the 

 stability of sulphates themselves. 



A normal alkali oximidosulphonate reacts generally as alkali 

 hydroxide towards salts the hydroxides of whose bases are insoluble ; 



