370 



Dr. J, Shields on Hydrolysis 



results which I obtained. The first column in the tables 

 contains the time t expressed in minutes since the beginning 

 of the reaction. The second and fourth columns C 2 — x and 

 C — x contain the concentrations of the salt and ester re- 

 spectively in hundredths of a gram-molecule per litre. The 

 third column contains x the quantity of ester which has under- 

 gone change, also expressed in the same unit. In the last 

 column will be found the constant expressed in arbitrary units. 

 Here it may be noticed that the first few values have been 

 neglected in accordance with the derivation of the formula. 

 From the mean value of these the characteristic constant K 

 has been calculated. A represents the amount of free alkali 

 in gram-molecules per litre, and besides this will be found the 

 percentage amount of salt which has been hydrolysed in the 

 solution experimented on and at the temperature at which the 

 experiment was carried out. It is conceivable that the 

 addition of ethyl acetate to the solution of salt would disturb 

 the existing equilibrium, but a discussion of this question is 

 reserved for a later part of the memoir. 



Potassium Cyanide. 



Solutions of this salt of four different concentrations were 

 examined, namely, \, J ? ^, and ^ normal. The tempera- 

 ture at which the experiments were made was 24°*2 0. The 

 value of k, the coefficient of velocity for potash at this temper- 

 ature, is 6'22. Nitrophenol was found to be the most suitable 

 indicator, and enabled me when titrating wuth decinormal 

 hydrochloric acid to observe the end point pretty accurately. 



N 



Y Potassium Cyanide. 



t 



C.-x. 



X. 



C-x. 









94-74 



o-oo 



3934 





4 



93-40 



1-34 



38-00 





16 



92-28 



246 



36-88 



(313) Xl0~ 7 



30 



91-40 



3-34 



36-00 



324 



90 



88-72 



6-02 



3332 



385 



210 



8640 



8-34 



3100 



337 



353 



84-20 



10-54 



28-80 



342 



580 



81-20 



13-54 



25-80 



378 









Mear 



i=353xl0" 7 



K=O000928. 



A = 0-00296, or 0'31 per cent, of salt hydrolysed. 



