134 G. J. BURROWS. 



the urea hydrochloride varied. In Table XI are given the 

 results for the degree of hydrolysis of urea hydrochloride 

 of various concentrations in this particular mixture at 25°C. 

 The values under h (calc.) were obtained from H = *345 r 

 which in turn was calculated from the value h = '810 found 

 for M/10 urea hydrochloride. 



Table XI. 



h 



h 



•494 



•664 



•760 



•785 



•810 



•861 



•927 



The agreement between the calculated and experimental 

 values of h is considered satisfactory. 



A comparison of the figures given in Tables IV and IX 

 shows that the degree of hydrolysis is not independent of 

 the nature of the substance which replaces the water as 

 solvent. Whereas the value of h in aqueous solution is *691 t 

 in 60 per cent, alcohol it is '603, and in 60 per cent, 

 acetone only '523. In the case of alcohol-water mixtures 

 the hydrolysis constant H is (approximately) proportional 

 to the total number of molecules of water + alcohol. This 

 is shown in Table XII, in which w represents the number 

 of gram molecules of water in the solution, and a the 

 number of gram molecules of alcohol. 



Table XII. 



Concentration 



of urea 

 hydrochloride 



M/2 



fci x 10 4 

 7-91 



fa x io 4 

 3-91 



M/4 



3-60 



2-39 



M/6 



2-38 



1-81 



M/8 



1-77 



1-39 



M/10 



1-42 



1-15 



M/16 



0-870 



0-749 



M/32 



0-438 



0-406 



factor 



h 



h (calc.) 



1-06 



•523 



•554 



103 



•684 



•675 



1-01 



•767 



•737 





•785 



•780 





•810 



[•810] 





•861 



•865 



... 



•927 



•925 



Alcohol % 



a 



w 



(a-i-w) 



U 



fl X 1()2 



HxlO 2 



(vol.) 



W 



w+a 











50-0 



50-0 



•773 



1-54 



1-54 



40 



6-25 



30-5 



36-75 



•593 



1-94 



1-61 



50 



7-83 



25-5 



33-33 



•536 



2-10 



1-61 



60 



9-22 



20-0 



29-22 



•458 



2-29 



1-57 



70 



10-75 



15-0 



25-75 



•378 



2-52 



1-47 



