1909-10.] Solutions of Tetra-propy 1-ammonium Chloride. 
515 
XXXVI. — Specific Volume of Solutions of Tetra-propyl-ammonium 
Chloride. By J. W. M‘David, B.Sc., Carnegie Research Scholar. 
Communicated by Professor James Walker. 
(MS. received June 7, 1910. Read July 4, 1910.) 
During the investigation of the viscosities of aqueous solutions of tetra- 
propyl-ammonium chloride, Taylor and Moore * noticed that the density 
of a concentrated solution was less than that of a dilute solution at the 
same temperature. The following investigation, undertaken at the 
suggestion of Dr W. W. Taylor, shows how the density depends on the 
concentration and temperature of the solution. 
Tetra-propyl-ammonium chloride was prepared from tetra-propyl- 
ammonium iodide. Silver chloride was added to an aqueous solution of the 
iodide and the mixture allowed to stand in the dark for some time. The 
tetra-propyl-ammonium chloride solution which was formed was then filtered 
off from the solid silver iodide and evaporated to dryness in a vacuum 
desiccator. The solid so obtained was a white crystalline substance which 
was very deliquescent. It was tested and found to be free from iodide. 
A number of solutions of various concentrations were then made up. 
By titrating with a standard solution of silver nitrate the concentration of 
each solution was obtained. Its density was next determined at four different 
temperatures, viz. 0° C., 25° C., 35° C., and 56° C., by means of a Sprengel 
pyknometer. The density of each solution was deduced from the formula 
,7 _ W'D _ *0012 (W'-W) 
r W W 
The values for the density of water were taken from Landolt and 
Bornstein’s Tables, pages 37 and 38. 
The concentrations of the various solutions and their respective densities 
at each temperature are as follows : — 
Concentration 
gms. per 100 gms. 
Solution. 
Density. 
0°. 
25 r . 
35°. 
56°. 
o-o 
•9999 
•9971 
•9942 
•9853 
0-93 
•9997 
•9968 
•9938 
•9850 
1-73 
•9995 
•99645 
•9933 
•98465 
3-12 
•99915 
•99595 
•9928 
•9839 
6-87 
•9991 
•9952 
•99195 
•9826 
9-75 
•99895 
•99445 
•9908 
•98155 
10-90 
•9992 
•99465 
•9910 
18155 
15-69 
•99965 
•9940 
•9901 
•9798 
23-98 
1-0030 
•99465 
•9902 
•9786 
27-70 
1-0055 
•9959 
•9909 
•9792 
* Proc. Roy. Soc. Edin., xxviii. p. 470 (1908). 
