290 Dr. R. A. Lehfeldt on the 



Phenol-water Mixtures. 



67*36 per cent, of phenol. 



t 50° 65° 75° 85° 90° 



Tv-p 0-5 0-4 2-2 5-6 8-2 



(tt-^/tt 0-005 0-002 0-008 0-013 0-015 



77*82 per cent, of phenol. 



t 70° 75° 80° 85° 90° 



7T-p 2-6 5-0 8-2 12-5 17-1 



(tt-^/tt 0-011 0-017 0-023 0029 0032 



82*70 per cent, of phenol. 



t 40° 50° 60° 65° 70° 75° 80° 85° 90° 



7T-p < 1-4 5-6 111 14-8 19-2 25-2 32-2 42-3 539 



(jr-jp)/*-.. 0-025 0-061 0-075 0-079 0082 0-087 0-091 0098 0-103 



90*46 per cent, of phenol. 



t 25° 40° 50° 60° 65° 70° 75° 



tt-p 1-9 9-1 17-5 31-7 43-2 53-5 68 6 



(tt-^V'tt... 0-081 0-165 0-190 0213 0-231 0-230 0-237 



A mixture containing 7*74 per cent, of phenol gave no 

 certain indication of a difference of pressure between the 

 mixture and pure water. On this point, however, more 

 reliable information is to be obtained with the Beckmann 

 apparatus. It will be noticed from the preceding figures 

 that the influence of the dissolved phenol becomes steadily 

 greater as the temperature rises, e.g. 82 per cent, of phenol 

 produces nearly twice as great a change of vapour-pressure 

 proportionally at 90° as it does at 50°. In agreement with 

 this the rise of vapour-pressures in dilute solutions of phenol 

 is more marked at 100° than at the lower temperatures at 

 which the vapour-pressure apparatus is available.- The result 

 of an experiment on the boiling-point is as follows : — 



Per cent, 

 phenol. 



Fall of 

 boiling-point. 



Corresponding 

 rise of vapour- 

 pressure, p — 7T. 



4-8 



9-0 



130 



16-4 



0-154 

 0-169 

 0-161 

 0-154 



4-1 

 4-5 

 4-3 

 4-1 



The general character of the results is sufficiently shown 



