in the Analogy between Solutions and Gases. 103 



The experimental result is 



0-38045 log C H2 co 3 -log C B a(Hco 3 ) 2 =K. 



3. Turning to Thomsen's investigation on the action of 

 sulphuric acid on sodium nitrate in solution (Thomsen's 

 Thermochemische Untersuchungen, i.), we find a similar agree- 

 ment. 



The reaction may be formulated thus : — 



Na 2 S0 4 + HN0 3 ^NaHS0 4 4-NaN0 3 ; 

 and Guldberg and Waage's relation requires 



log C Na ,so 4 + log C H no 3 — log C NaHS o 4 — log C NaN o 3 = K. 



Now 



«Na 2 S0 4 =l*91 J 2HN03=1'94 J 2NaHS0 4 =l*88 ; and lNaN0 3 =l'82;. 



and the equation becomes 



1-05 log C Na2 so 4 + l'06 log C HN o,-l'03 log C NaHS o 4 



— log C NaN o 3 =K,. 

 which is almost identical. 



If we express the relation thus : — 



Na 2 S0 4 + 2HNO^H 2 S0 4 + 2NaN0 3 , 



Guldberg and Waage's formula becomes 



log C Na ,so 4 + 2 log C H No 3 —log Ch 2 so 4 — 2 log C NaNO =K^ 

 and we obtain : 



log C Na2 so 4 + 2-03 log Chnos-I^O? log Ch 2 so 4 



-1-91 log C NaN03 =K; 

 Again an almost absolute agreement. 



4. Ostwald's investigation {J. prakt. Chem. [2] xix.p. 480) 

 on the action of hydrochloric acid on zinc sulphide, according, 

 to the formula 



ZnS + 2HCl^H 2 S + ZnCl 2 , 



leads, when the following values are ascribed : 



*hcp=1-98; zh 2 s=1'04 ; i ZnClt =2-53 



to the equation : — 



3*96 log CVi-1'04 log 0^-2-53 log C ZnC , 2 =K. 



It is evident that the concentrations of the sulphuretted' 

 hydrogen and the zinc chloride are equal, for only hydro- 

 chloric acid and zinc sulphide are initially present. The 

 result is expressible by taking the volume V, in which a 

 known amount of hydrochloric aoid was dissolved, as the* 



