38 Conductivities and Viscosities in Pure and in Mixed Solvents. 



MERCURIC CHLORIDE. 



The conductivity of aqueous solutions of mercuric chloride is too 

 small to be measured, but in formamid, on account of its greater dis- 

 sociating power, the conductivity is measurable and increases as dilu- 

 tion increases in the usual way up to the N/400 solution. The con- 

 ductivity values for the N/1000, N 1600 and N/3200 solutions clearly 

 result from some decomposition, probably of the solvent. The con- 

 ductivity of barium chloride at complete dissociation is 55.86 at 25. 

 The large value 134.49 for the N/1000 solution of mercuric chloride 

 shows that it is not due to dissociation. Assuming that at complete 

 dissociation the conductivity of mercuric chloride would be of the same 

 order of magnitude as of barium chloride, the dissociation of the N/4 

 solution would be about 1 per cent, increasing to about 7 per cent for 

 the N/400 solution. Silver chloride is precipitated in the N/400 solu- 

 tion by silver nitrate. By standing in the sunlight for a short time, a 

 heavy precipitate of metallic silver is formed, showing again the reduc- 

 ing action of formamid. 



To recover the solvent from the mercuric chloride by vacuum dis- 

 tillation required several more distillations than usual. Metallic 

 mercury was found in the receiver after the first distillation, showing 

 again the reducing action of formamid. It is possible that the liber- 

 ated chlorine formed a salt with the formamid which was easily dis- 

 sociated, since the conductivity of the first fraction of the distillate 

 was very high and was lowered only a small amount by successive dis- 

 tillations. Repeated distillation, however, yielded the solvent used 

 for the caesium solutions. 



COBALT BROMIDE. 



The green, anhydrous cobalt bromide gives a pink solution in forma- 

 mid as in water. After the determinations were made, a mixture of 

 solutions was distilled to recover the formamid. The mixture con- 

 tained mercuric chloride and cobalt bromide. As already stated, the 

 mercuric chloride was reduced to metallic mercury. The dry residue 

 in the distillation flask had the brilliant blue color of anhydrous cobalt 

 chloride, showing that the free chlorine from the mercuric chloride had 

 replaced the bromine in the cobalt bromide. 



GESIUM NITRATE AND CHLORIDE. 



For several years past this laboratory has been unable to obtain any 

 csesium salts for its investigations on conductivity and viscosity. 

 Recently some csesium sulphate was obtained through the cooperation 

 and courtesy of Prof. James Lewis Howe, of Washington and Lee Uni- 

 versity. The sulphate was converted into the nitrate and chloride, 

 and the conductivity and viscosity of solutions of these salts were 

 determined. The results are recorded in tables 22 and 23. 



