206 



ELECTRICAL RESISTANCE OF ACETIC ACID 



At temperatures below the eutectic point no liquid exists 

 between the electrodes and as the amount of ice present is 

 very small in comparison with the acetic acid (solid): there 

 should exist a true temperature coefficient of resistance for the 



1 d Ti 



solid acid. Defining this as — - -^ it can be determined 



Rt d T 



from the curve 2, by graphical methods and it is found to 

 vary from 0. 3 @ — 43°C to 0.25 (A, -70°C. The writer^ found 

 the temp. coefT. of ice to vary from 0.6 @ -2° to 0.12 at -12° 

 and with lower temperatures it increases in value. It thus 

 appears that solid acetic acid is like ice in that it has a very 

 great temperature coefficient of resistance. The temp, coeff. 

 for sample 2 in the liquid phase was calculated in a similar 

 manner and found equal to 0.04 («, 14°C. 



To determine the effect of adding considerable quantities 

 of water to the acid, the tube was filled with a 2% solution of 

 water in acetic acid, (sample No. 3), and measurements were 

 made at different temperatures. 



A comparison of the specific resistance, temp, coeff. and 

 the melting points for samples 1, 2 and 3 is given in table 4. 



TABLE 4. 



Sample. 



State. 



M. P. 



Temp. 



Res. Sp. 



Temp.- 



COETT. 



1 



Liquid 



15.9 



14° c. 



1.3X10' 



.04 



2 



,, 



16.4 



14 



3.8X10' 



.04 



3 



:i 



13.2 



14 



1.2X10' 



.03 



1 



Solid 





12 



1.7X10' 





2 



" 





12 



8.9X10^ 





3 



u 





12 



2.2X1'.' 





1 



a 





-80 



1.0X10'= 



2.5 



2 



it 





-80 



9.9X10'"- 





3 







-80 



8.4X10" 





1 Trans. X. S. Iii.s. of Sc. XIII., part 2, page 143. 



