54 



CONDUCTIVITIES AND DISSOCIATIONS 



This solution of the above-mentioned problems was worked out by 

 Jones and Springer and Smith jointly, and with the same apparatus. 

 We used a 500 c.c. or a 200 c.c. flask calibrated in this way for 50 at 

 20, in which to make up our mother solutions. In the higher temper- 

 ature work it was noted that bubbles of air formed on the electrodes, 

 especially at 50 and 60. These were removed by carefully shaking 

 the cells before making the readings. 



VALUES. 



The values of the limiting conductivities of the monobasic acids were 

 found directly from the ^ values of their sodium salts. It has been 

 shown by experiment that the conductivities of sodium salts, made up 

 by the titration method, which, as already stated, was used in this 

 work, agree with the conductivities of solutions which were made up 

 directly from the dry, solid, sodium salt. The ^ values of the acid 



485 

 480 

 475 

 470 

 465 

 460 

 455 

 365 

 360 

 355 

 350 

 345 

 230 

 225 

 220 



555 

 550 

 545 

 540 

 535 

 530 

 525 

 520 

 515 



410 

 405 

 '.00 

 395 

 390 

 305 



3<l<) 

 2W 

 280 



H ') 12 M 16 18 20 22 24 26 28 30 



FIG. 20. Limiting conductivities. 



were obtained from those of the sodium salts by a very simple method. 

 It consists in subtracting the constant of the sodium ion from the 

 limiting conductivity value for the sodium salt, and then adding to this 

 value the constant for the hydrogen ion. This may be readily accom- 

 plished in actual work by using this equation: ju, acid = /** HC1+M* 

 Na salt of acid ^ NaCl. 



To calculate the value of ju, for hydrochloric acid and sodium 

 chloride at the various temperatures at which the work was done, the 

 equations of White and Jones were used : 



For sodium chloride, /* = 63.04 + 2.04 t - 0.00823 t~ 

 For hydrochloric acid, /* = 245.4 + 6.06 t - 0.00776 t 2 

 Table 16 gives all the values of the acids with which Smith worked. 

 The ju, values of dibasic acids could not be determined by this method. 

 The sodium salts of dibasic acids do not yield a maximum value of 

 conductivity at dilutions at which work could be done. Comparison 

 of the (j. values of the acids which Jones and several of his co-workers 

 have studied, shows that those acids with the largest number of atoms 



