. r >4 Drushd <>/></ Lvnhart — Metallic Alkyl StilpAates. 



Ba(C,H 6 SOJ 3 + H a > BaS0 4 + HC 2 H 6 S0 4 + C s H B OH. (5) 



If the hydrolysis is made in the presence of hydrochloric 

 acid there is present from the beginning an equilibrium mix- 

 ture in which both ethyl barium sulphate and ethyl sulphuric 

 acid nndergo hydrolysis, or possibly chiefly ethyl sulphuric 

 acid in the presence of high concentrations of hydrochloric 

 acid. As we expected, we found experimentally that when 

 strong hydrochloric acid is poured into a solution of ethyl 

 barium sulphate at room temperature a precipitate immediately 

 forms which is chiefly barium chloride. We may express the 

 decomposition of ethyl barium sulphate in aqueous hydrochloric 

 acid solution by the following equations : 



Ba(C s H 6 S0 4 ) 2 + 2HC1 ±+ BaCl, + 2HC 2 H 6 S0 4 , (6) 



and 2HC 2 H 6 S0 4 + 2H 2 ^=± 2H 2 S0 4 + 2C,H,OH ; (7) 



also Bad, + H 2 S0 4 > BaS0 4 + 2HC1, (8) 



and Ba(C 2 H 6 S0 4 ) 2 + H 2 S0 4 ► BaSO, + 2HC,H,S0 4 . (9) 



Summing up and removing common terms from both members 

 of the resulting equation, we have, as before, the simple 

 expression : 



2Ba(C,H 6 S0 4 ) 2 + 2H 2 > 2BaS0 4 + 



2HC a H 5 S0 4 + 2C,H 6 OH,* (10) 



or Ba(C 2 H s S0 4 ) 2 + H 2 > BaS0 4 + 



HC 2 H 6 S0 4 + C 2 H 6 OH. 



In either case (in the presence or absence of hydrochloric acid) 

 there is an increase in the acidity of the reaction mixture over 

 its initial acidity of -J re gram equivalents of acid for x grain 

 equivalents of barium sulphate formed in any time t. By 

 titrating the acid solution filtered off from the precipitated 

 barium sulphate in a number of instances, it was found that 

 this relation invariably exists. Consequently in the velocity 

 equation the concentration of ester (i. e., Ba(C 2 H 5 S0 4 ) 2 and 

 HC„H 5 S0 4 ) undergoing hydrolysis is decreased in time t by x 

 and increased by -J a?, hence its concentration may be written 

 A— x+^x, where A is the initial concentration of ester in 

 gram equivalents per liter. The formation of ethyl sulphuric 

 acid accelerates the reaction also by increasing the acidity of 

 the mixture, hence for any time t the acid concentration may 

 be written B+^x, where B is the concentration of hydrochloric 

 acid used, in gram equivalents per liter. 



If the velocity of the reaction is proportional to the total 

 concentration of ester undergoing hydrolysis and the total con- 



* This equation was also derived by Krernann, loc. cit. 



