Conductivities of Some Unusual Salts. 



AMMONIUM SULPHOCYANATE. 



157 



The amount of sulphocyanate present in the original solution was 

 found by weighing the silver sulphocyanate formed on treating a portion 

 of the solution with silver nitrate. (See table 92.) 



LITHIUM CHROMATE. 



The chromate in this solution was determined as it was in the case of 

 sodium chromate. (See table 93.) 



RUBIDIUM IODIDE. 



The iodine was determined as silver iodide. (See table 94.) 



TABLE 94. Rubidium iodide. 



DISCUSSION OF RESULTS. 

 CONDUCTIVITIES. 



Electrical conductivity in solutions of electrolytes depends on the 

 number of ions present and on the velocities of these ions. The 

 velocities, other conditions being the same, depend upon the size and 

 mass of the ion and upon the viscosity of the medium. This leads 

 to the conclusion that a salt showing a high conductivity must be 

 dissociated into a great number of ions, or the ions in solutions must be 

 of such a size and mass that they have a great velocity. 



It can be seen from the above tables that certain salts, notably 

 trisodium phosphate, sodium pyrophosphate, ammonium chromate, 

 and potassium ferricyanide, show very high conductivity. The first 

 of these compounds is strongly hydrolyzed even at low temperatures. 

 The breaking down of complexes by hydrolysis gives rise to a great 

 number of ions also in the case of the pyrophosphate. It is interesting 

 to compare the conductivity of the trisodium phosphate with that of 

 the corresponding potassium compound. While both show very high 

 conductivities at all temperatures, the conductivity of the potassium 

 salt is greater than that of the sodium. We would expect this from 



