376 



Dr. J. Shields on Hydrolysis 



Borax. 



Several experiments were made with solutions of borax? 

 but the results were by no means as satisfactory as could be 

 desired. The chief difficulty seemed to be in the want of a 

 suitable indicator. After trying about twenty I finally selected 

 litmus as the one which gave the best results. Next to litmus 

 came rosolic acid. I first of all prepared a solution of litmus 

 of a certain purple tint to act as a guide or standard, and 

 then I added acid to the solution under examination until it 

 became of the same tint. I shall only give one series of 

 experiments with a -^ molecular normal solution of borax, so 

 that some conception may be formed as to the amount of 

 hydrolysis in solutions of borax. 



The temperature of experiment was 24°*2 C, and the co- 

 efficient of velocity for sodium hydrate corresponding to this 

 temperature is 6*23. 



N 

 32 



(mol.) Borax. 



t. 



C a -*. 



cc. 



C—r. 









5-85 



00 



48-70 





4 



5-82 



0-03 



48-67 





8 



5-72 



0-13 



48-57 



(30)xl0- 6 



30 



5 55 



030 



48-40 



(22) 



188 



410 



1-75 



46-95 



120 



1190 



2-73 



312 



45-58 



86 



2885 



1-40 



4-45 



45-25 



95 



4375 



0-95 



4-85 



43-85 



94 









Mean 



= 99xl0" 6 



K=0-00050. 



A =0*000738, or 0'92 per cent, of salt hydrolysed. 



The Influence of Dilution on the Amount of Hydrolysis. 



The table which follows contains the general results of the 

 foregoing experiments and shows the effect of dilution on the 

 amount of hydrolysis. 



The first column gives the approximate concentration of 

 the solution, the second the amount of free alkali in the solu- 

 tion in gram-molecules per litre, and the last the percentage 

 amount of salt hydrolysed. 



