Manchester Memoirs, Vol. Ixi. (19 1/), l^o. ^. 



III. Note on the Action of Hydrogen on Sulphuric Acid. 



By Francis Jones, M.Sc, F.R.S.E., Y.CS. 



{Read January (jth, kj//. k'ccc'n'cd for fuhUcatioii January 15th, iQi?-) 



Many years ago, when working with hydrogen prepared 

 by electrolysis, I noticed that the gas, after being left in con- 

 tact with strong sulphuric acid, had a distinct odour of sulphur 

 dioxide. It appeared obvious that the hydrogen had reduced 

 the sulphuric acid, and I proceeded to ascertain what work, if 

 any, had been done on the subject. I found that Faraday 

 (Phil. Trans., 1834) had examined the action of nascent 

 hydrogen on sulphuric acid. He stated that strong sulphuric 

 acid is a very bad conductor of electricity, but if subjected 

 to the action of a powerful current, oxygen a[3pears at the 

 anode, and hydrogen and sulphur at the cathode. These 

 results were confirmed by Gladstone and Tribe in a paper 

 communicated to the Chemical Society in 1879. They give 

 a detailed account of their study of the behaviour of nascent 

 and occluded hydrogen on sulphuric acid, and arrived at the 

 opinion " that these hitherto supposed different states of the 

 element are very closely related, if not identical — that in fact, 

 the activity of the so-called nascent hydrogen is only the 

 consequence of its intimate association with the metals em- 

 ployed to bring about the liberation of the element." They 

 decomposed strong sulphuric acid (98 per cent. H. SO4) with 

 variable battery power, and obtained results agreeing with 

 Faraday's, but when they used one cell only, they obtained 

 very little gas at the anode in ten days, and not a trace of 

 sulphur or gas at the cathode, but the liquid there contained 

 an appreciable amount of sulphurous acicl. A similar reduc- 

 tion of sulphuric acid was effected by occluded hydrogen. 



G. T. Warner, in 1873.(6"/^^;;/. Isleivs, XXVIIL, 13) found 

 that sulphur dioxide was evolved in quantity when sulphuric acid 

 was distilled in a current of hydrogen, and that the reaction 

 began at a temperature of 160° C. He also found that sul- 

 phuric acid and hydrogen, when treated together for twelve 

 hours in a sealed tube to 205° C. also yielded sul})hur dioxide. 



Berthelot, in the Compt. Rendu for 1897, also examined 

 this reaction. He found that a slow current of hydrogen passed 

 for an hour through concentrated sulphuric acid at the ordinary 

 temperature did not produce sulphur dioxide, but that pro- 

 longed contact between the acid and the gas brought about 

 the reaction. Further, that no reaction occurred with the dilute 



Fcl>ruary 2jfh, 1^17. 



