90 Conductivities and Viscosities in Pure and in Mixed Solvents. 



STATEMENT OF PROBLEM. 



The plan was to investigate the difference in the velocities with 

 which free water and combined water saponified an ester under the 

 following conditions : 



(1) Time and concentration of the salts kept constant, temperature 

 varying. 



(2) Concentration of the salts and temperature constant, time 

 varying. 



(3) Time and temperature constant, concentration of salts varying. 



The conditions were so regulated that the percentage of ester saponi- 



+ 



fied was always small, the H ions of the acid formed, being in rela- 



+ 



tively large numbers as compared with the H ions from water, would 

 suppress the ionization of water and themselves effect the saponification. 



EXPERIMENTAL. 

 APPARATUS. 



The reactions were allowed to take place in 100 c.c. Jena bottles 

 with ground-glass stoppers. These bottles were suspended in constant- 

 temperature baths, very similar to those employed by Davis and 

 Putnam. 1 The thermometers were compared with a standardized 

 thermometer. The temperatures of the baths were kept constant to 

 within 0.02 of a degree. The baths were stirred at first by a gas- 

 engine, later by an electric motor. The solutions were measured by 

 means of carefully calibrated pipettes; 10 c.c. burettes were used for 

 measuring the ester, and 50 c.c. burettes for titration purposes. All 

 measuring flasks were made of Jena glass and were calibrated by weight. 

 The solutions were always kept in Jena bottles. 



SOLUTIONS. 



As stated before, only solutions which gave neutral reactions with 

 litmus were used. The salts were Kahlbaum preparations recrystal- 

 lized. The solutions of slightly hydrated salts were made up by weight, 

 the strongly hydrated salts by analysis and dilution to the required 

 normality. 



A concentration was chosen arbitrarily, such that solutions of all the 

 salts to be investigated could be obtained, i. e., 2 normal. Later it was 

 found to be necessary to change this concentration to normal, using 

 also the more dilute solutions, half -normal and quarter-normal. The 

 amount of the solution that contained an amount of water equal to the 

 free water was determined as follows: 10 c.c. of the solution was weighed 

 and from this the weight of 1 c.c. was determined. The weight of the 



Carnegie Inst. Wash. Pub. No. 210, 117 (1915). 



