86 Conductivities and Viscosities in Pure and in Mixed Solvents. 



From the results obtained with the ester and pure water, as compared 

 with those from solutions of the salts, we could study the effect of 

 rise in temperature on the hydrated salts. 



HISTORICAL. 



The effect of neutral salts on reaction velocities was studied first 

 by Arrhenius, 1 who investigated the hydrolysis of ethyl acetate as 

 effected by bases, and by bases in the presence of one of their salts. 

 He found that in the case of 1 /40 normal potassium hydroxide, sodium 

 hydroxide, and barium hydroxide, the addition of their halogen salts 

 decreased the velocity of the reaction, and that the addition of sulphates 

 increased the velocity. 



Spohr 2 studied the effect of neutral salts on the inversion of cane 

 sugar by acids, and on the saponification of an ester by bases. He 

 found that the addition of neutral salts increased the velocity of the 

 former reaction, but diminished the velocity of the latter. 



Arrhenius 3 also studied the influence of neutral salts on the inversion 

 of cane sugar by acids and obtained results similar to those found by 

 Spohr. The effect of the salt was greater with dilute than with more 

 concentrated acids. 



Euler 4 obtained results very similar to those found by Spohr. 



The above work led to the study of the effect of neutral salts when 

 the acid and base were absent. 



Smith 5 measured the dissociation of organic dibasic acids by meas- 

 uring the rate at which the acids invert cane sugar. He also studied 

 the effect of neutral salts on the reaction when the acids were absent, 

 and found that while salts of weak acids did not affect the reaction 

 differently from pure water, the salts of strong acids, such as potassium 

 chloride and sodium sulphate, produced a large effect. 



Kellogg 6 studied the problem of the effect of neutral salts on the re- 

 action velocity of the saponification of ethyl acetate. The ester and the 

 solutions were sealed in glass tubes and put in a constant-temperature 

 bath at 100. The tubes were then opened and the contents titrated 

 with phenolphthalein and sodium hydroxide. To get the amounts of 

 the solutions of the salts which should contain an amount of water 

 equal to the free water, the density of the salt solution was determined, 

 its percentage of water content figured, and the amount to be added 

 calculated. Kellogg found that in the more dilute solutions the specific 

 influence of the salt is greater. As the solutions become more concen- 

 trated the increase in reaction velocity grows less, and in the case of 

 4-normal potassium chloride the hydrolysis is slower than in pure 

 water. He found a decrease in the accelerating power from potassium 

 chloride, to potassium bromide, to potassium iodide, which is in the 



t. phys. Chem., 1, 110 (1887). 3 Ibid., 4, 237 (1889). 5 Ibid.,25, 144 (1898). 

 2 Ibid., 2, 194 (1888). *Ibid., 32,348 (1900). 6 Journ. Arner. Chem. Soc., 31, 



403, 886 (1909). 



