in Aqueous Salt-Solutions. 385 



the mean values have been employed in calculating the 

 characteristic constant. 

 If ? in the equation (5), 



dx 1 1_ K(C 2 -«k) 

 dt'C—x h~~ x 



we substitute for C 2 — x and 0— x their mean values 9*316 

 and 48'49, which were obtained from a series of experiments 

 made at 24°-2 0., where &=6'23, we get : 



dx 1 1 



d ' 48-49* 6*23 



9-316 K 



which on integration gives the solution 



6-23 x 48-49 x 9-31 6K = 



_x{ 



■x 2 



h-k 



Having got the characteristic constant K, equation (7) 

 enables us to determine A, the amount of free soda in the 

 solution at the beginning, expressed in gram-molecules per 

 litre. The solution was titrated with the help of phenol 

 phthalein. 



In this case of course x, which is expressed in hundredths 

 of a gram-molecule per litre, was measured directly. The 

 values of x in the following table are the means of two con- 

 cordant sets of experiments. 





10 



Sodium Acetate. 





t. 



C 2 -x. 



X. 



C-x. 









9-52 



o-ooo 



48-70 





1224 



9-46 



0-060 



48-64 





3952 



9455 



0-065 



48-635 





6882 



9 385 



0-135 



48-565 



2-58X10- 6 



21252 



9-20 



0-320 



48-380 



4-93 



25550 



9-20 



0-320 



48-380 



4-06 



34160 



9-165 



0-355 



48-345 



3-72 



41290 



9-14 



0-380 



48-320 



3-51 



Mear 



i = 9-316. Mean=48-49. Me 



an=3-76xl0" 6 - 



K = O0000000668. 



A = 0-00000798, or 0-008 per cent, of salt hydrolysed. 



According to these measurements and calculations, it will 

 be seen that in a tenth normal solution rather less than yJ-Q 

 per cent, of sodium acetate is hydrolysed into free acid and 



