Freezing-points of Solutions of Water in Formic Acid. 15 



Table II. [continued). 



F.-P., 



c . 10 9 , 



t m 



K . 10*. 



P, 



C w . 10 3 , 



t. 



m, 



°C. 



0°Hg. 



°l 



1 o 



c Hg. 



°C. 



*. m.p. 1. 





110-0 



211 





902 







6733 





122-7 



8-36 















1236 



8-79 















124-3 



956 















1296 



1218 















132 6 



13-80 















134-4 



15-15 















140-9 



19-54 















1279 

 1416 

 1503 

 1566 



3 53 



9-73 



1406 



1785 





1034 







7-829 





200-2 



1-89 





15-78 







12-72 





207 6 



416 















2230 



8-62 















228-7 



1060 















237-7 



13-56 















2481 



17-13 















345-2 

 349-6 

 358-8 

 3722 



9-67 

 10-65 

 12-75 

 16-24 





24-52 







2205 



Fig. 2 shows the dependence between specific conductivity 

 (c) and the temperature (t). The first number for each 

 solution (put in brackets) is calculated for £ = F.-P., supposing 

 the curves are straight lines, that being so at least for the 

 lower temperature. The temperature-coefficient " K " is 

 calculated for the first seven solutions from all the observa- 

 tions, for the others only from the observations at the low 

 temperatures. 



The diagram (fig. 2) shows some very interesting results. 

 The points for the specific conductivity (c) of different solu- 

 tions at the temperature of freezing are on a straight line, 

 which could be easily extended to the freezing-point of the 

 anhydrous acid, which is, no doubt, that of Raoult, freezing 

 at 8°-52. 



The equation of this straight line, using observations from 

 1 to 14, is 



c*= 64-77 -6-937 F.-P. 



(1) 



