Part VIII. 



THE CONDUCTIVITY AND IONIZATION OF HYDROCHLORIC, NITRIC, 



AND SULPHURIC ACIDS UP TO 306, AND OF PHOSPHORIC 



ACID AND BARIUM HYDROXIDE UP TO 156. 



88. OUTLINE OF THE INVESTIGATION. 



In this article, after a brief description of experimental details, are given 

 the results of conductivity measurements with aqueous solutions of sul- 

 phuric, phosphoric, and nitric acids, and barium hydroxide at various 

 concentrations at temperatures up to 156. The measurements were for 

 the most part made at 18, 25, 50, 75, 100, 128, and 156, and at the 

 concentrations 100, 50, 12.5, 2, and 0.5 milli-normal. Conductivity meas- 

 urements with nitric and sulphuric acids at the still higher temperatures of 

 218 and 306, and with hydrochloric acid at 260 and 306 were also 

 made, and these are included with the others. Some results with sul- 

 phuric acid extending up to 218 which were obtained somewhat earlier 

 in this laboratory by Mr. Yogoro Kato are also here presented in con- 

 junction with our own. 



Finally, the results are all discussed with reference to the ionization 

 of the various substances and the equivalent conductance of their ions at 

 different temperatures. 



89. DESCRIPTION OF THE APPARATUS AND METHOD. 

 CONDUCTIVITY-VESSEL. 



The conductivity bomb (No. 1) employed in most of this work, was the 

 first one made in this laboratory as described in Part II of this series. It 

 had been used just previously by Mr. Yogoro Kato for the investigation 

 described in Part VI and for his measurements with sulphuric acid pre- 

 sented below. It then contained an open cylindrical platinum-iridium 

 electrode arranged as shown in figure 13, Part III ; and in that form will 

 be designated Cell I below. For our experiments this electrode was 

 replaced by a flat platinum-iridium electrode placed at the bottom of a 

 quartz cup, 1.45 cm. in height and 1.40 cm. in diameter. The vessel in this 

 form will be called Cell n. For some of our later measurements another 



239 



