118 Conductivities and Viscosities in Pure and in Mixed Solvents. 



DISCUSSION. 



There is one difficulty in the study of this problem that must first 

 be pointed out, i. e., the necessary use of a strong alkali (half -normal 

 solution of sodium hydroxide) with which to titrate the acetic acid 

 formed. This necessarily introduces some error, since a difference of 

 0.1 c.c. in reading the burette would make a difference of over 1 per 

 cent. A more dilute solution of an alkali could not be used, since too 

 large a quantity of such a solution would be required. 



The rate of the decomposition of the anhydride is at first very rapid, 

 then gradually decreases as the hydration approaches completion. 

 In this respect the reaction differs from similar ones studied, such as 

 the hydrolysis of esters, since in these cases the reactions are reversible. 

 There is also a marked increase in the rate of decomposition of the 

 anhydride with rise in temperature. 



The values obtained for the salt solutions, having a fixed quantity of 

 water, are compared with those obtained with pure water. All of the 

 very concentrated salt solutions show a marked decrease in the rate of 

 decomposition of the anhydride. This retardation is greater with the 

 two hydrated salts used than with the non-hydrated salt. However, 

 with the more dilute solutions, molar, etc., this is not the case. Mag- 

 nesium chloride and potassium chloride hinder the rate of decomposi- 

 tion to about the same extent, this being slightly greater with the 

 solutions of magnesium chloride. Calcium chloride, on the other hand, 

 shows a slightly accelerating action. 



CONCLUSION. 



These relations are interesting, but as yet no general or final con- 

 clusions can be drawn. The problem is to be investigated farther, 

 using a much larger number of salts, both hydrated and non-hydrated. 



