Reilly and HiCKiNBc'TTOM — Distillation of Volatile Fatty Acids. 127 



In the following table the recorded values for acetic acid [ibid.) are given, 

 and also the values after correction for ionisation .— 



It can be seen from Tables I-IV that by applying a correction for 

 the ionisation of the acid in the solution a (;onstant is obtained. The value 

 of the constant thus obtained is practically independent of the concentra- 

 tion. Thus the principal variation in the distillation constants of the volatile 

 fatty acids with dilution can be accounted for by taking the ionisation into 

 consideration. The values in fig. 2 are the comparative results from several 

 experiments, but the figures are not absolute. 



0-80 



0-70 

 0-60 

 0-50 

 0-40 

 0-30 



60 



50 



40 



30 



20 



10 



Volume (in litres) containing 1 gram molecule. 

 Fig. 2. 



The Addition of Certain Acids and Salts. 



It has been shown by Stein' that the addition of sulphuric acid to an 

 aqueous solution of acetic acid increases the distillation constant. 



'J. pr. Chem., 1913, 88, 83. 



SOIENT. PBGC. B.D.S., VOL. XVI., NO. Xt. B 



