DISTRIBU’I’IOS O F MERCCRIC CHLORID BETIVEES TOLCENE ,IND I’I’XTER
BY OLIVER IV. B R O W S
Three ineasiirements by Skinner1 seem to s l i o that ~ ~ a fairly constant distribution ratio is obtained when mercuric chlorid is added to mixtures of ether and water. I t seemed desirable to see whether the same general relations held true when other organic liquids were substituted for ether and I have therefore made some measurements with toluene and water. T h e toluene was purified by distillation, the water was the ordinary distilled water of the laboratory. T e n cubic centimeters of each solvent were placed in test-tubes and varying amounts of mercuric chlorid added. T h e test-tubes were corked securely, shaken from time to time and allon-ed to conie to equilibrium at constant temperature. Five cubic centimeters of each of the liquid layers were then pipetted off and the aiiiount of niercnric chlorid in each mas determined by running in an excess of potassium iodid solution and titrating back with normal mercuric chlorid. It n - a b found necessaq- to make a correction of 0 . 2 cc for each j cc of toluene owing to the solubility of mercuric iodid in toluene. T h e amount of this correction was determined by preliminar? experiments with known solutions. I t was found that no appreciable error was introduced by adding a small or a large excess of potassimn iodid. I n analyzing the toluene solutions one oaght to add quantities of water varying with the amount of salt in solution. This, of course, is not very practicable and the difficulty was avoided by adding always a large excess of water. In Table I &re the experimental data. Under CI are grams of mercuric clilorid in five cubic centimeters of the ayueJour. Chem. SOC.61,542
I
rS92).
solutions and under Cz the corresponding values for the toluene solutions. T h e last solution was saturated.
011s
TABLE I Temperature 24’ -
~~
0.0221
0.0366 0.0390 0.0596 0.0908 0. I883 0.18;7 0.3344
3j 0.00244 0.001
’
16.4 15.0
0.00406 0.006jo 1 0.0146 0.0149 0.0264
~
13.9 12.9 12.6 12.7
~
1
11.2
1
11.1 11.0
10.8
10.4
1
10.9 10.6
1
11.3
T h e ratio of the concentrations is not constant, the concentrations in the water phase not increasing- quite so rapidly as those in the toluene phase. variation of three percent in the ratio is quite within the probable experimental error ; but that would account only for the fluctuations in two successive figures and would not change the general trend of the results. On the other hand the ratio CI/Cz seems to be constant. According to the Nernst theory this means that there is a slight dissociation in the aqueous solution. Unfortunately one cannot draw any conclusions in regard to the dissociation of mercuric chlorid either from Grotrian’s’ conductivity measurements or from Beckiiiann’s* boiling-point studies. I t is therefore impossible to determine, at the present time, n-hether the ratio of the concentration of the undissolved salt in the two phases is constant. Covnell University Ivied. Xnn. 18, 177 ( I S S ~ ’ ~ . Zeit. phys. Chern. 6, 437 (rS90).
