Intelligence and Miscellaneous Articles. 54:5 



ACTION OF POTASSIUM AND SODIUM ON SULPHUROUS ACID. 

 BY MM. FORDOS AND GELIS. 



When potassium or sodium is thrown into an aqueous solution of 

 sulphurous acid, they act upon it in the same way as on pure water ; 

 potash and soda are formed and hydrogen is evolved, which inflames ; 

 the alkalies combining with the sulphurous acid to form sulphites, 

 which remain in solution ; if the experiment be made in a tube with 

 the pure metals, the phaenomena are similar, hydrogen and sulphites 

 being obtained. 



The reaction takes place with so much violence, and the rise of 

 temperature is so considerable, that it is natural to suppose that these 

 two circumstances influence the results, and that if the reaction were 

 less vivid different results would be obtained ; for such bodies as 

 combine at common temperatures do not act upon each other when 

 the temperature is raised. 



MM. Fordos and Gelis endeavoured therefore to bring potassium 

 into contact with aqueous sulphurous acid, under such circumstances 

 as should not raise the temperature, and they succeeded in the at- 

 tempt, by operating with freezing mixtures and treating sulphurous 

 acid with potassium which had been previously combined with metals 

 that were incapable of decomposing water or sulphurous acid by 

 themselves ; or in other words, they used the alloy of potassium and 

 antimony, and that of potassium and mercury. 



These alloys decompose water which has been well cooled, regu- 

 larly and without inflammation ; when they are treated with very 

 dilute sulphuric acid containing sulphurous acid, hydrogen mixed 

 with sulphuretted hydrogen is disengaged, the presence of which is 

 ascertained by the smell and its action upon acetate of lead. 



If these alloys be treated with water containing sulphurous acid 

 only, hydrogen is still disengaged, for the action cannot be so regu- 

 lated as to obtain the perfect reduction of the sulphurous acid ; but 

 no sulphuretted hydrogen is evolved, and acids precipitate sulphur in 

 abundance from the solution ; consequently there are formed, under 

 these circumstances, both a sulphite and a hyposulphite. — Journ. de 

 Ph. et de Ch., Octobre 1843. 



ACTION OF ZINC ON SULPHUROUS ACID, SULPHITE OF ZINC. 

 BY MM. FORDOS AND GELIS. 



An aqueous solution of sulphurous acid readily attacks zinc, espe- 

 cially when the metal is in filings and the solution is concentrated ; 

 there is increase of temperature but no gaseous product. Fourcroy 

 and Vauquelin have stated, that when the action is rapid a notable 

 quantity of hydrosulphuric acid gas is evolved ; but it is easy to prove 

 that when this occurs it is from a totally different cause from that 

 which they assign to it. Well- washed and recently prepared sul- 

 phurous acid never produces this effect ; it occurs, on the contrary, 

 when the acid employed contains sulphuric acid. 



In order to obtain a concentrated solution of zinc in sulphurous 

 Phil, Mag. S. 3. No. 155. Suppl. Vol. 23. 2 N 



