THE ELECTRICAL CONDUCTANCE O F SOLUTIONS I N METHYLAMINE AND ETHYLAMINE; THE FLUIDITY O F AMMONIA, METHYAMINE AND SULP H U R DIOXIDE AND THE FLUIDITY O F CERTAIN SOLUTIONS I N THESE SOLVENTS BY FRED F. FITZGERALD
P A R T I.-CONDUCTANCE OF SOLUTIONS IN METHYLAMINE AND E T H Y L A M I N E
Introduction An unexpected behavior of methylamine solutions was observed by Gibbs, wh? measured the electrical conductance of silver nitrate and potassium iodide in this solvent. He found the molecular conductance of silver nitrate, beginning with concentrated solutions, first t o rise, with increasing dilution, t o a maximum value, thence to fall t o a minimum, thence to rise again presumably toward a final maximum after the familiar manner of salts in aqueous solution. Following Gibbs’ observation the plan was inaugurated in this laboratory of measuring the electrical conductance of concentrated solutions in a number of electrolytic solvents in order t o determine the extent t o which the behavior observed by Gibbs is followed by solutions in other solvents. Returning t o a study of the electrical conductance of liquid ammonia solutions Franklin2 found that although the phenomenon observed by Gibbs does not recur in the case of all liquid ammonia solutions, still, the characteristic trend of the molecular conductance curve was found t o mark the behavior of certain salts in this solvent. Certain results recorded by Walden and Centnerzwer in their paper on sulphur dioxide as a solvent3 led Franklin to Franklin and Gibbs: Jour. Am. Chem. SOC., 29, 1389 (1907). Zeit. phys. Chem., 69, 272 (1909). Bull. Acad. Imp. Sci. St. Pktersbourg, [5] 15, 17 (1901); Zeit. phys. Chem., 39, 5 1 3 (1902); Zeit. anorg. Chem., 30, 145 (1902).
62 2
Fred F . Fitzgerald
expect a similar behavior on the part of solutions in this solvent. Reference to the record' of his investigations will show that this surmise was justified. These investigations upon sulphur dioxide solutions are of especial interest in that they show the complete trend of these peculiar conductance curves from the most concentrated realizable solutions up to and including those of the highest dilution as measured by Dutoit and Gyr.' With continued dilution, beginning with highly concentrated solutions, the molecular conductance first rises rapidly t o a maximum then falls to a minimum, thence rises, at first rapidly and then a t a diminishing rate until the final maximuni characteristic of an aqueous solution is reached. Keither in ammonia nor in any other solvents which show these maxima and minima, had any of the solutions which exhibit the first maximum and the minimum theretofore been carried t o sufficiently high dilutions to establish the second maximum experimentally. Conductance maxima and minima similar to those brought to light in this laboratory have been found to characterize 'certain other solutions. Lewis and Wheeler3 in their investigations upon liquid iodine as an electrolytic solvent found that potassium iodide solutions show a molecular conductance which with increasing dilution rises t o a conspicuous maximum and then declines, showing distinctly a minimum, which Ihtter, however, in view of the uncertainty attaching to measurements on the more dilute solutions, was not emphasized by the authors. A distinct maximum and minimum has been found by Archibald4 t o characterize the molecular conductance curve of salicylic acid in liquid hydrochloric acid, and recently McBain and Taylor5 and Bowden6 have observed the same be-
' Jour. Phys. Chem., 15,675 (1911). Jour. Chim. Phys., 7, 189 ( 1 9 0 9 ) . Proc. Am. Acad., 41,419 (1906). Jour. Am. Chem. SOC.,29, 1429 (1907). Zeit. phys. Chem., 74, 206 (1911). Jour. Chem. SOC.,99, 194 (1911).
Electrical Conductance of Solutions
623
havior on the part of aqueous solutions of sodium palmitate and sodium stearate. A considerable number of investigations may be cited in which the observed anomalous behavior on the part of the molecular conductance curve may be explained by assuming that in each case the descending portions only of the complete curve have been observed. For example, diminishing molecular conductance with increasing dilution is shown in the early measurements of Kablukoff' on solutions of hydrochloric acid in ether and amyl alcohol; in the measurements of Plotnikoff on solutions of antimony bromide and phosphorus pentabromide in bromine ; of Sackur3 on solutions of hydrochloric acid in cineol; of Franklin and Kraus4 on solutions of certain metallic cyanides in liquid ammonia; of Jones and Carroll5 on hydrochloric acid in mixtures of methyl alcohol and water; of MacIntosh and Archibald@and of Archibald' on certain solutions of liquefied halogen acids; and of Kahlenberg and Ruhoff8 on cadmium iodide and ferric chloride in amylamine. In other instances there has been observed a rise t o amaximum followed by a continuous depression of the molecular conductance with increasing dilution. Such behavior was found by Franklin and Kraus' to characterize certain metallic cyanides in solution in liquid ammonia; and by Kahlenberg and Ruhoff" to be characteristic of solutions of silver nitrate in amylamine; Walden" has observed a similar behavior on the part of solutions of tetraethylammonium iodide in Zeit. phys. Chem., 4, 492 (1889). Plotnikoff: Ibid., 48, 2 2 0 (1904). Ber. chern. Ges. Berlin, 35, 1242 (1902). 'Jour. Chem. SOC., 2 7 , 191 (1905). Carnegie Institution of Washington Pub., 80, 51 (1907). 29, 655, 1416 (1907). B'Jour.Am. Chem. SOC., Phil. Trans., 205A, 1 2 0 (1906). *Jour. Phys. Chem., 7, 254 (1903). LOC.cit. l o Jour. Phys. Chem., 7, 254 (1903). Zeit. phys. Chem., 54, 131 (1906).
'
624
Fred F . F itzgerald
acetaldehyde and acetic acid, and S h i m 1 on the part of solutions of lithium chloride in ethylamine. In all these measurements the assumption seems justified that the conditions happened t o permit the realization of the first maximum only of the complete conductance curve. In the investigation of still other solutions the minimum only of the complete curve has been observed as will be seen, for example, by reference t o the measurements of the conductance of zinc cyanide in liquid ammonia by Franklin and Kraus’ and to the work of Archibald3 on a considerable number of solutions in liquid hydrochloric acid and liquid hydrobromic acid. With the object in view of adding to the data necessary for elucidation of the mechanism of the conduction of concentrated solutions, the writer has undertaken the measurement of the electrical conductance of solutions in methylamine and ethylamine through as wide a range of concentrations and temperatures as possible under available working conditions. The writer feels rather apologetic for the meagerness of results obtained but pleads in extenuation the experimental difficulties attached t o working with solvents of low boiling points; the major portion of the time available for the work being consumed in acquiring the necessary manipulative I skill. Jour. Phys. Chem., 11, 537 (1907). Loc. cit. Jour. Am. Chem. Soc., 29, 665, 1416 (1907). It is interesting to note in connection with the work of Archibald t h a t just as phosphine and stibine are successively poorer ionizing solvents than ammonia and as hydrogen sulphide is likewise a much poorer ionizing solvent than water, so hydrobromic acid appears a poorer ionizing solvent than hydrochloric acid which in turn must be a poorer ionizing solvent than hydrofluoric acid. Hydrofluoric acid being the hydride of the typical member of the eighth group of the periodic system ought to be a conspicuously better electrolytic solvent than the succeed-, ing members of the group, just as water and ammonia greatly excel the hydrides of the other members of the seventh and sixth groups respectively. The conspicuous power of hydrofluoric acid as a solvent for certain salts and the fact that the isolation of fluorine was made possible to Moissan by the good conducting power of a solution of potassium fluoride in liquid hydrofluoric acid are facts which make such a view plausible.
Electrical Conductance o j Solutions
625
Apparatus and Method of Manipulation The apparatus which was used for the measurement of the conductance of solutions .in methyl and ethylamine was essentially the same as t h a t used by Franklin1 and Franklin and Kraus,2 except that the conductance cell was made much smaller in order t o conserve the expensive solvents used. The Thermostat.-The conductance cell was kept at a constant temperature in a bath of liquid ammonia, or in a mixture of ammonia and water, contained in a Dewar cylinder A, Figure I . Tube M is for introducing liquid ammonia into the bath. Tube N is for emptying, partially or completely, the bath after each series of measurements. +, The tube V is for the escape of ammonia gas. A t h e r m o m e t e r which has been tested at t h e Reichsanstalt is shown a t B. The temperature was adjusted by the use of a vacuum pump, attached t o V in the same manner as described by Franklin,3 except t h a t " it was not regulated automatically. The Cond4ctance Cell. -The conductance cell is provided with three electrodes, two lower ones, XX, a t the bottom of the cell for Fig. I use with solutions of high resistance, and a smaller one W above, which is used in connection with one of the lower electrodes for good conducting solutions. These three electrodes are connected with the measuring apparatus by means of heavy copper wires passing down through the tubes, X' X', and a third, not shown in the figure; contact with the electrodes being obtained through mercury in the P.
~
-
~
Zeit. phys. Chem., 69, 2 7 2 (1909). * A m . Chem. Jour., 23, 277 (1900). a LOC.cit. I
-
626
Fred F . Fitzgerald
bottom of these tubes. The resistance between the upper electrode and one of the lower set of electrodes is increased by enclosing the upper electrode in a glass cylinder open a t each end as shown in the figure. The cell is constricted a t J t o permit more accurate setting at that point. Marzipulation. l-The details of a series of measurements are as follows: The bath A is first filled with liquid ammonia. The cell is then thoroughly washed by use of the solvent. To this end the amine is condensed in the cell through R’, K”’, K’, and is then forced out b y application of hydrogen pressure on the surface of the liquid, setting stopcocks K’. K’”, and KIV, to deliver through R’” t o a waste vessel. This operation is repeated until the cell is absolutely clean. A weighed quantity of solute is now introduced through the neck of the cell U, a small long-stemmed funnel carrying the solute well toward the lower end of the cell. The tubulure is then sealed off with a small gas flame as it was found that the methylamine decomposes any cork stopper very quickly at the higher temperatures used. Solvent is then distilled into the cell through R’, K”’, and K’ until the pointer J is slightly more than covered. After thorough stirring to ensure homogeneity, the surface of the solution is adjusted to pointer J. This stirring and adjustment is accomplished b y forcing a current of pure, dry hydrogen, brought from the generator b y way of R”, KIV, K”’, K’, through the solution. During these operations the stopcock K’ and the gas exit P”’ are opened or closed as exigencies of the operations require. After temperature equilibrium has been established, the resistance of the solution is measured, the method of Kohlrausch with alternating current and telephone being used. This resistance is for a temperature of -33.5 O . The temperature of -
~For more complete descriptions of apparatus used in the investigation of liquids of low boiling points the reader is referred to earlier papers from this laboratory. Am. Chem. Jour., 20, 836 (1898); 23, 277 (1900); 24, 83 (1900); 26, 499 (1904); 27, 830 (1905); 27, 851 (1905); 28, 1395 Jour. Am. Chern. SOC., (1906); 29, 656 (1907); 29, 1389 (1907); Jour. Phys. Chem., 11, 553 (1907); X I , 559 (1907); 15, 675 (1911); Jour. Am. Chem. SOC., 29, 1693 (1907); Zeit. phys. Chem., 69, 272 (1909).
Electrical Conductance of Solutions
627
the bath is then raised t o -15 O by forcing out part of the liquid ammonia from the Dewar thermostat A, and replacing it with a solution of ammonia in water until the temperature The temperature is then adjusted is slightly above -15’. t o - 1 5 ~ by use of the vacuum pump. The level of the solution in the ce.11 is then readjusted t o pointer J, and the conductance measured. The operations thus described are repeated for the temperatures o’ and 15’. After the conductance a t + I 5 O has been measured the temperature is lowered to -33.5 O, the surface of the solution is adjusted t o pointer J and the resistance again measured. The purity of the solvent and the accuracy of the operations are thus checked. For the next dilution the solvent is distilled into the apparatus until the surface of the solution stands slightly above pointer S’, when the series of operations described above is repeated. After the measurements a t the dilution corresponding to pointeF S”have’been performed i t is necessary t o remove a known portion of the solution from the cell. To do this, hydrogen pressure is turned on t o the surface of the solution through stopcock P”; PI and K”, K”’ and K I V , being set t o deliver liquid through R”’ into the waste flask. As the level of the liquid in the cell approaches pointer J the rate of emptying is slowed down by partly closing stopcock K”. The delivery of liquid stops automatically when the surface of the liquid reaches the point of the delivery tube J, leaving a known fraction of the solution in the cell. The stopcock P’ is then momentarily opened through P”’ to relieve the cell of the hydrogen pressure. After the removal of this portion of the soh-’ tion the conductance of the solution at -33.5 O is again measured to make sure that the concentration has not altered during manipulation. The series of operations thus described are then repeated in the manner described above until the desired number of dilutions has been made. The tubes connecting stopcocks K’ and K” with the neck of the conductance cell are for the purpose of equalizing the pressure in all parts of the cell. When the dilutions have been carried as far as desired,
+
,
628
Fred F . Fitzgeyald
the cell is completely emptied by application of hydrogen pressure to the surface of the liquid through P”, and setting K’, K N ’ , KIV, R’”, t o deliver the solution into the waste vessel. The cell is washed clean in the manner described above, the sealed end of the U tube is cut off and a new neck sealed in its place when the apparatus is ready for beginning a new series of measurements. Cell Constants.-The volumes to marks J, S‘ and S“ were 4.95, 7 . 2 8 and 9 . 8 8 cubic centimeters, respectively. The resistance capacity for the high resistance pair of electrodes was 1 6 . 3 3 Kohlrausch units, and for the low resistance pair 0.I 137 Kohlrausch units. The Solvents.-The methylamine used was partly a Kahlbaum preparation, partly prepared in this laboratory by Mr. R. W. Poindexter, t o whom the writer hereby acknowledges his obligations. The amine was made on rather a large scale by the method of Hofmann, chlorinated lime beirig substituted for the more expensive bromine and potassium hydroxide. The crude product was purified by fractional distillation, followed by treatment with mercuric oxide and redistillation. Between 400 and 500 grams of pure solvent were prepared. The attempt was made t o use methylamine and ethylamine prepared by Schuchardt. The specimens were found t o contain ammonia and other impurities which rendered their use impossible.
The Conductanoe of Methylamine Solutions The fact that methylamine is an electrolytic solvent was first noted by Franklin and Kraus‘ who observed its power as a solvent and made approximate measurements of the conductance of a tenth-normal solution of potassium iodide from - 6 3 O up t o $ 1 5 0 ~ . Gibbs later took up the study of methylamine as a solvent not only for inorganic salts but also Am. Chem. Jour., 24, go (1900).
Electrical Conductance of Solutions
629
for organic compounds of the most varied types.l Gibbs found t h a t methylamine is a remarkably good solvent for a large variety of compounds, especially for compounds of carbon. He also noted t h a t many of these solutions are conductors of electricity. Following upon this work, Gibbs2 undertook quantitative measurements of the electrical conductance of methylamine solutions and discovered the then unique behavior of solutions of silver nitrate. Unfortunately, however, his work was suddenly terminated by the great San Francisco earthquake of April, 1906. Following upon the work of Gibbs, Mr. D. H. Hoagland took up the investigation of the electrical conductance of methylamine solutions but was forced by circumstances to abandon the work after making a few measurements. His results, which have not hitherto been published, are included in the data given below. The writer has undertaken a continuation of the work of Gibbs and Hoagland, but instead of extending his measurements to a large number of solutes, has chosen two solutes only and has measured their conductance through as wide range of dilution and temperature as the means at his disposal would permit. In the tables which follow are given in the first column the dilutions in liters per gram molecule, in columns 2 , 3 , 4 and 5, the molecular conductances in Kohlrausch units at the respective temperatures indicated. Data given under I, 11, 111, etc., represent independent series of measurements. Silver Nitrate.-This salt is extremely soluble in methylamine, a solution containing 69.2 grams to IOO cc. of the solution being yet unsaturated a t temperatures between -33 O and 15'. The presence of the least trace of moisture causes the separation of a black precipitate. For some reason which must remain unexplained the results here recorded for the conductance of silver nitrate solutions at oo are not in as close agreement with those of Gibbs as could be desired.
+
-
Jour. Am. Chem. Soc., 28, 1395 (1906). Ihid., 29, 1381 (1907).
Fred F . Fitzgerald
630
5.449 10.63 20.74 40.48 0.2806 0.5475 I .069 2.084
21.80
20.04 19.08 19.56 4.945 16.13 23.01 24.32
I I
25.18 22.19 20.44 20.23
1
8.67
~
'
. 22.17
29.38
1
26.81 22.74 20.44 20.03
I I 1
12.36 27.51 34.13
i ~
27.41 22.19 19.55 18.41 .-
16.52 32.29 38.56 34.95
Potassium Iodide.-The conductance of potassium iodide in methylamine at oo has been studied by Gibbs;I his work was, however, cut short by the great earthquake before measurements were carried t o concentrated solutions. The salt used by the writer was from a specimen by J. T. Baker, dried by gentle ignition. It is to be noted that there is a discrepancy between the results obtained by the author, on the one hand, as against the results of Gibbs and Hoagland on the other which the writer is at a loss to explain. In view, however, of the better control of the conditions which experience has permitted the writer t d achieve it is LOC.cit.
Electrical Conductance of Solutions
631
believed t h a t the later results are deserving of greater confidence. _
~
_
~
___
~
_
_ -_ _ _
~
_
__
_
_
~ . J o - ~ _~~
0.6094 I . 190 2.320 4.527 8.833 17.24 33.62. 6q.61
31.12 32.97 28.49 21.68 17.40 15.06 14.64
46.49 43.96 33.34 22.93 15.80 '2.57 11.44
42 , 9 0 41.74 33.90 23.45 17.26 13.91
11.92 -
28.21 55.04 107.4 209,5 408.9 797.9 1557.0 3038.0 5927.0
14.63 15.49 17.72
I
21.77
I
27.79 35.63 45.86 58.73 74.53
',
,
1
1
.56 11.78 73.43 16.52 21.38 27.91 37,55 49.83 66.40 I I
,
,
Fred F . Fitzgerald
632
Lithium Nitrate.-The strongest solution crystallized t o a’solid mass after exposure for at a temperature of zero degrees. It is much at higher temperatures. Four separate series ments were made as follows:
-_
_
I1
Y/IOOO
il
‘1
y/1030
I -
1
10.3
0.513
1
_ _15.6 __~
0.665 1.22
-
11
~
~__
1 I
Y
A
I11
0.278
______~_
I
of this salt a short time more soluble of measure-
19.8 20.8
-
1.17 2.18
I‘ -
20.6
IV
1I
8.77 16.2 29.9
11.4 9.59 8.83
1I
Lithium ChZwide.-This salt is less soluble than lithium nitrate. A solution containing z millimols per cubic centimeter is approximately saturated a t zero degrees. But one series of measurements was made : _ _ $o/ ~I 0 0 0
0.493 0.91 1.68 3.11
9.5’ 12.20
10.47 7.98
I1 1
I 5.74 10.59 19.55
-
* 6.67 5.20
4.73
-
Electrical Conductance of Solutions
633
Mercuric Iodide.-A laboratory specimen of this salt, which received no other treatment than thorough drying, dissolved abundantly t o a colorless but somewhat milky solution. On dilution the solution cleared up. But a single series of measurements was made : __
_. ~~
~
I
A
(P/IOCO
0,797 '1.046 1.537 2.22
3.01
~
.
,
-
2.82
2.31 1.72
~
_ ~
ij
I (I
~--. ___
___ I
'I
2.85
4.18 j,36 7.88
A
1,
1.38
1 j
o.S6 0.67
1.02
Metadinitvohenzene.-This substance, when freshly dissolved, forms a permanganate colored solution which changes gradually to a deep blue. Dilute solution's are red. As observed by Franklin and Krausl for solutions in liquid ammonia, a freshly prepared solution of metadinitrobenzene in methylamine shows a gradual increase in conductance on standing. After some ten or .fifteen minutes the conductance becomes constant. After each dilution the conductance increases for some time before becoming constant. Three series of measurements were made :
634
Fved F . Fitzgwald
,
The Electrical Conductance of Ethylamine Solutions The conductance of solutions of silver nitrate, ethylammonium chloride and lithium chloride were made a t four temperatures, - 3 3 . 5 " , -15O, oo and + l g O , and through as wide a range of concentration as conditions under which the work was carried on would permit. The following tables expressing the dilution in liters per contain the data, (210-~ gram molecule and 3 the molecular conductance in Kohlrausch units. Silver Nitrate.-This salt dissolves readily in ethylamine producing a clear, colorless solution, provided the salt and solvent are quite dry. The merest trace of moisture gives a black precipitate. The solution very readily undGrgoes reduction, '' silvering ' ' the apparatus, especially when acted upon by direct sunlight. The conductance of ethylamine solutions of silver nitrate a t oo has been measured by Frederick Shinn.' For reference his data are plotted in the figure with those given herewith.
3,953 7.886 15.73
' Jour.
~
~
4.320 2.683 1.677
Phys. Chem.,
11,
1 ,
5.400 3.181
i
,1.818
537 (1907).
1 I
~
6.141 3.454 1.939
6.719 3,690 1.939
Electrical Conductance of Solutions
635
erick Shinn.l For reference his data are plotted on the same plate with the writer's data. -_ _ __ _____.I
.I
a
-
____ -
_ _ _ _~
0.4215 0.8224 1.604 3.131
-_
~
j
-33.5'
~
~
I
~
--
~
1
,
~
1
1.279 0.8484
1
~
~
2.523 4,923 9.607 .r4.8g
1.032
I
i
0.561
0.3001 0.1564
-15O
' 0
I ___
1
+IS0
-
1 2.080 2.447 I 2.66r I 1.763 I 1.911 I, 1.835 0.9915 0.976 0.8052 ~- -. I1 ___ , ~ _ ~ _ _ _ _ ~ _ . 1.275 , 1.293 , 1.105 1 0,5933 0.5294 1 0.4048 0.2387 i 0.1722 0.2923 0.1400 , 0.1093 . I 0.08168 -2
I
\
I ,586
~
2.001
\
~
~
~
~
Ethylammonium Chloride.-A specimen of Kahlbaum was used which received further treatment beyond thorough drying. - --___
~
~
I
_ _ ~ -. _.~
_-
________
0.7676 I ,497 2.922 5 702 11.13
3.692 2.606 1.285
I
21.71 _
_
42.36 ~ ~
~ _ _
-~
0.2368 0.4619 - 0.9014
0.5711 0.3099 0.2316 0.2163 _ _ ~ _ _ _
~
I 1 I 1
4.675 2.921 I . 261 0.5359 0.2804
'
0.2122
, ___0.1872
111... . 2.345 4.869
- 3 ~ ~ _ ~ - -._ ~ .
3.535
5.294 5,630 2.992 ' 2.886 1.181 I 064 0.4640 I 0,4054 0.2441 0.2001 0.1824 1 0.1525 0.1638 1 0.1371 --
_
~~
4.325
_
~
I ~
~
3.597 5.993 4.696
I
i
5,050 6.968 4,986
Zoc. cit.
At these temperatures not all the salt present in the cell was in solution. .4t -33.5O a portion of the solute separated from the solution.
636
Fred F . Fitzgerald
Discussion of Results.-The data given in the above tables are plotted in Figures 2-6, in which ordinates represent molec-
Fig. 2
1
Electrical Conductance of Solutions
63 7
P
CONOUC riviry
of
AgNOa
IP*
LO9
CHaNH2
'4Iov3
I
0
I
Fig. 3
I
I
2
3
Fred F . Filzgerald
638
ular conductances and abscissas the logarithms of the dilutions. It seems worth while t o call attention to a few points of interest in connection with these measurements. I n the first place it is to be noted that the molecular conductance of the solutes studied, both in methylamine and ethylamine, show the maximum ‘observed by Gibbs for silver nitrate in methylamine and by Franklin for certain I I2
-
IO
-
8 -
6 -
,I >
0 4-
I i
Fig. 4
solutions in ammonia and sulphur dioxide. I n the case of methylamine solutions the maximum is followed by a minimum, but a final maximum which presumably should be reached at high dilution could not be realized because of the extreme dilution to which measurements would have t o be carried to accomplish complete ionization in this solvent. I n the case of solutions in the poorer ionizing solvent, ethylamine, the measurements could not be carried t o sufficiently
Electrical Conductance o j Solutions
639
high dilutions t o demonstrate with certainty the existence of a minimum of molecular conductance. The curves representing molecular conductances of solutions in this solvent are seen t o approach the axis of abscissass with no indications,
2.6
* 2.2
1.8
1.4
1.0
6
.2
SWINN, 0
I
Fig. 5
excepting in the case of silver nitrate, of a rise with continued dilution. In the second place, it will be noticed, as was found to be'ithe case by Franklin for solutions in sulphur dioxide' that I
Jour. Phys. Chem., 15, 675 (1911).
640
Fred F . Fitzgerald
the conductance temperature coefficients for concentrated solutions are positive and that as the solutions are diluted change sign after the manner recorded for solutions in sulphur dioxide. For methylamine solutions the measurements of molecular conductance at the higher dilutions as repre-
Fig. 6
sented b y the curves show a tendency t o arrange themselves in the same order as for concentrated solutions. Finally, it is a matter of some interest t o institute a comparison between the typical compound, water with its derivatives, methyl alcohol and ethyl alcohol, on the one
Electrical Conductance of Solutions
641
hand, and ammonia and its derivatives, methylamine and ethylamine, on the other. Methylamine and ethylamine are in a sense the methyl and ethyl alcohols of Franklin's ammonia system and as such they should show variations in their properties from the typical substance, ammonia, in many respects similar to those shown by methyl and ethyl alcohols with respect to water. That the analogies thus indicated are certainly more than purely formal are shown by the work of Gibbsl on the solvent powers of methylamine and by the conductance measurements recorded in this paper. Water is the solvent par excellence for salts and it possesses practically the highest ionizing power of any known solvent. Methyl alcohol dissolves many salts and its ionizing power, while much below water, is still fair, while its power as a solvent for compounds of carbon is far above that of water. The powers of ethyl alcohol as a solvent for salts and as an ionizing agent are considerably below those of methyl alcohol, while its power as a solvent for the compounds of carbon are somewhat superior t o the simplest alcohol. Similar relationships apparently exist between ammonia and its alkyl derivatives. Ammonia is an excellent solvent for many salts although its power in this respect is by no means as wide as t h a t of water, and while by no means as powerful an ionizing agent as water it is nevertheless one of the conspicuously good ionizing agents. I n its capacity as a solvent for the compounds of carbon i t is interesting t o note a conspicuous superiority over water. As is to be expected from the formal relationship between ammonia and its alkyl derivatives, it is interesting t o find in methylamine a substance which on the one hand is distinctly inferior t o ammonia as a solvent for salts and in its ionizing power, while on the other hand as a solvent for the compounds of carbon it not only surpasses ammonia but apparently the alcohols themselves. Ethylamine is a poorer solvent for the few salts studied than is methylamine and its ionizing power .is certainly much below Jour. Am. Chem. SOC., 28, 1395 (1906).
* Vide Gibbs: Jour. Am. Chem. SOC.,28, 1395 (1906).
Fred F . Fitzgerald
642
that of the simplest amine. Its capacity as a solvent for compounds of carb,on has not been studied but from the manner in which it attacked the shellac varnish on a shelf upon which a portion of the amine was spilled i t seems safe to assume conspicuous power for it in this respect. From the experience of this laboratory the writer is of the opinion that the amines will prove themselves valuable solvents.
PART 11.-THE
FLUIDITIES OF AMMONIA, METHY LAMINE A N D SULPHUR DIOXIDE
Introduction The exceptionally high values for the maximum molecular conductance of salts in solution in liquid ammonia as obtained by Franklin and Krausl, and the experimentally measured ionic velocities which were shown by Franklin and CadyZto be from two and a half to three times as great in ammonia a t - 3 3 . 5 O as in water a t 18O, have been assumed t o be due t o the low viscosity of liquid ammonia as compared with water. It seemed desirable therefore t o make direct experimental determinations of the viscosity of this solvent. Furthermore, in view of the success of Dutoit and Gyr3 in following the molecular conductance of salts in solutions in liquid sulphur dioxide to their final maximum values a t high dilution, it was determined to include measurements of the viscosity of liquid sulphur dioxide in order to test Walden's rule4 in its application to this solvent. Measurements were begun on the viscosity of rnethylamine and its solutions, for the reason that it was deemed easier t o manipulate this solvent and thus gain experience necessary for successfully working with the other two solvents. A result of this order of taking up viscosity measurements ' A m . Chem. Jour., 23, 2 7 7 (1900); Jour. Am. Chem. SOC., 27, 191 (1905). Jour. Am. Chem. SOC.,26, 499 (1904). Jour. Chim. Phys., 7, 189 (1909). p. 6 4 j .
Electrical Conductance of Solutions
643
has been t h a t data for,ammonia and sulphur dioxide are much more meager than those pertaining t o the former solvent. The measurements were made in accordance with the well known Poiseuille method. A modified form of the Ostwald viscosimeter was used, descriptions of which together with an account of the method of manipulation are given in the third part of this paper.
Experimental Results Methylamine.-Five determinations of the density of methylamine at oo gave 0.6869, 0.6860, 0.6861, 0.6862 and 0.6869, mean 0.6864 as the value of this constant referred t o water at 0'. The time of outflow of water a t oo for the viscosimeter used was 157 . 5 seconds. The time of outflow of methylamine at the same temperature was 30.5 seconds. The viscosity of water at oo according to Thorpe and Rodger' is 0.01778. Calculated in accordance with the formula given below' the viscosity 17 of methylamine is found to be 0.002364, and since fluidity is the reciprocal of viscosity, the fluidity 9 of methylamine at o o is 423. I . Liquid Ammortia.-The form of apparatus and the method of manipulation used in the determination of the fluidity of ammonia are described in detail in the third part of this paper. With two viscosimeters, each calibrated for two times of outflow, the following results have been obtained, assuming 0.6823 as the specific gravity of liquid ammonia at -33. Column I gives the number of the viscosimeter used in making the measurement; column I1 the mark t o which the level of the liquid in the viscosimeter was adjusted; column I11 the observed time of outflow for water at oo for the corresponding level; column IV the time of outflow for ammonia at -33.5 O, and columns V and VI, the corresponding calculated viscosity and fluidity, respectively : Landolt-Bornstein-Meyerhoffer, Physikalisch Chemische Tabellen. P., 649. Determination by the author. Cf. p. 654.
Fred F . Fitzgerald
644 -
I
I
I
I
3
J
Ja
3
'
1 ~
I
203.6 170'7 244.4 284.0
~
-33.5' -10.5' -k
Ja
I
0.1'
1 1
1'
49.9 40.3 37.7
1 1
1
I
37.6 44.5
I ~
E:: i
1.5174 1,4613 1.4350
Vide Viscosimeter Constants, p. 659. Zeit. angew. Chem., 1899, 275.
'1
i
0.002672 0.002651 2669 2656
0.005508
0.004285 0.003936
374.3 377.3 374.6 376.5
' I
181.6 233.4 254. I
Electrical Conductance of Solutions
645
The Product qd, Waldenl has found t h a t for a considerable number of non-aqueous solvents the product of the viscosity of the solute into the maximum molecular conductance of his normal solute, tetraethylammonium iodide, is a constant independent of the nature of the solvent and of the temperature. It becomes desirable therefore to determine whether this rule holds for the non-aqueous solvents whose viscosities are recorded above. Walden finds that his normal electrolyte gives more concordant results for the product '1 A m than do such binary salts as the iodides of sodium and potassium, facts due, as he plausibly shows, t o the higher molecular volume of tetraethylammonium iodode. Unfortunately, however, tetraethylammonium iodode is insoluble in liquid ammonia and its maximum molecular conductance in liquid sulphur dioxide is unknown, thus rendering impossible a comfor these solvents with the constant calculated parison of 71 A , by Walden. However, Walden has calculated the value of the product of the maximum molecular conductance of potassium iodide in a number of solvents into the viscosity of the respective solvents which are included in the table given herewith together with the corresponding data for liquid ammonia and liquid sulphur dioxide. A comparison of the values for q A W for ammonia and sulphur dioxide with the data given by Walden shows that these solvents, like water, must be accepted as exceptions t o the rule, the values obtained being intermediate between the values for water and 0.650 the mean of the value given by Walden for the remaining solvents given in the table. Whether a solute of much higher molecular volume will give more concordant results must be left t o the future for determination. Walden' makes use of the relationship expressed by the equation :
Zeit. phys. Chem., 55,
* LOC.cit.
207
(1906); 78, 257 (1911).
Fred F . Fitzgerald
646 _ _.-~_ ~
Solvent
Temp.
~
___
____
Sulphur dioxide
1 -15
0,003936
-10.5
0.004285
1-33.5
0.005508
1
i Watere -~ -
~
0.00452 I ' 0
'
Ammonia
71
~
18
1
25
Methyl alcohol Ethyl alcohol
972 )1.130 Io.961
I i
I.
0.00266
-33.5
j I
0.937
I..
I
0.01054
0.00891 ( L, ' wvJ
"-
1 0 . 1 0.0180 0.0125
18
35.0
153.0
1(-0.676
71.5
0.679
Kcetone .- y
~
Acetonitrile
Pyridine
1 '2
I
,
0 5-
o 25
1 I
0.00308 0.00442 0.00345
0.0136 0.00894
127
0.970 I . 117 ~i0.905 0.928 0.938 1,057 I .38 1.39 ____. I b . 697 jo.679 0.630 0.616
216"0 10.0
0.652 0.647
2 0~ 1 . 0_ I -____ __ _ 0.693
Interpolated from author's measurements. Dutoit and Gyr: Jour. Chim. Phys., 7, 189 (1909). Calculated from Franklin's data (Jour. Phys. Chem., 23, 2 7 7 (rgoo)), by means of Ostwald's formula, Am = (B~ZA,LV~-A,2AlV,)/~~l~-VzAzzVl), that is, on the assumption that at high dilutions Ostwald's dilution law is followed. Calculated from Franklin's data by means of Walden's formula. Value given by Franklin and Iiraus (Am. Chem. Jour., 23, 288 (1900)) for potassium bromide. e Highest value obtained by Franklin and Kraus for potassium bromide uncorrected for conductance of solvent. Calculated by means of Ostwald's formula from data for potassium bromide of Franklin and Kraus. Calculated by means of Walden's formula from data of Franklin and ICraus for potassium bromide. Data for water and succeeding solvents taken from Walden's paper.
'
Electrical Conductance of Solutions
647
and apparently with very satisfactory results, for calculating doo for solutions in which it is impracticable t o determine the maximum molecular conductance experimentally. Especially interesting and tending to fix one's confidence in the use of this formula are Walden's recalculations of the results of Dutoit and Dupersthuis' which bring the values of '7 dm for these measurements into harmony with his rule. Calculations of rj d m from the experimental results of Franklin and Kraus on liquid ammonia and of Franklin on liquid sulphur dioxide however fail to bring these solvents into line, and it is moreover difficult to believe that the high values obtained can in reality represent the truth with respect t o the maximum molecular conductance in these solvents.
PART 111.-THE FLUIDITY AND DENSITY OF METHYLAMINE AND LIQUID AMMONIA SOLUTIONS Methylamine Solutions The nature of the solvent to be investigated rendered necessary the construction of a special form of viscosimeter which is shown in Fig. 7. A D, E, R and F are the capillary tube and the cistern, respectively, of the viscosimeter proper. The two branches are connected above by way of C t o prevent any escape of the volatile solution and t o exclude atmospheric air. H is a vessel in which the solutions are made up and of which the volumes to the respective glass pointers are known. The stopper in the neck of this vessel is held in place against the internal pressure by means of a cap which screws down over the collar cemented t o the neck of the tube. During the operations of making up the solutions and observing the flow of the liquid through the capillary, the apparatus was immersed in a Dewar Fig. 7 Jour. Chim. Phys., 6 , 7 2 6 (1908).
648
Fred F . Fitzgerald
cylinder filled with water and crushed ice which is kept at constant temperature with the aid of a mechanical stirrer. Manipulation,.-Af ter weighing the viscosimeter it is placed in a thermostat and connected to a supply of methylamine contained in a steel cylinder, by means of a small lead tube attached t o the viscosimeter at B by means of sealing wax. A weighed quantity of solute is then introduced through the opening at A after which the opening is closed by means of a cork stopper and the metal cap is screwed down. Methylamine is then distilled into leg H until the surface of the solution is accurately adjusted to the top of the first glass pointer, care being taken before final adjustment t o insure homogeneity of the solution. The apparatus is then removed from the ice bath, permitted t o come t o room temperature and weighed. The data necessary for calculating the specific gravity and dilution of the solution thus become known1 Again cooling the legs of the viscosimeter to zero, a portion of the solution is poured from H into leg F until the latter is filled t o the mark R, after which the apparatus is returned t o the thermostat and immersed t o a point just below bulb D. To determine the outflow time of the solution stopcock C is closed and bulb D is barely touched with a tuft of cotton moistened with liquid ammonia. This causes the solution to rise into bulb D. Stopcock C is then opened so as to place the two parts of the apparatus in communication and the time of outflow read as usual with an Ostwald viscosimeter. For a second dilution the solution in F is poured back into H, and F thoroughly washed by distillation of the solvent from H to F and subsequent pouring back into H. More . methylamine is then distilled into the apparatus through tube B until the cell is filled to pointer 2 . The solution is thoroughly mixed and the volume adjusted t o pointer 2 as described above for pointer I . The apparatus is again weighed, The fact t h a t all or a considerable portion of air in the apparatus is replaced by gaseous methylamine introduces no considerable error in density determinations, since the density of methylamine vapor is but little greater than the air displaced.
Electrical Conductance o f Solutions
649
the solution poured over into F up t o mark R and the time of outflow determined. The procedure thus described is repeated for dilution three. After the third dilution the methylamine is distilled off and recovered; the tube cleaned, when the apparatus is in readiness for a new series of measurements. The methylamine used was part of a kilogram made by Kahlbaum and was the same as used by Franklin and Gibbs.l The purchase of this material was rendered possible by a grant fron the Trustees of the Bache Fund t o whom acknowledgements are here made again. Cell Constants.-The volumes of the side tube H t o the three pointers I , 2 and 3 were 4.35, 8.13 and 12.08 cubic The time of outflow for centimeters, respectively, a t 18'. water a t oo was 1 5 7 . 5 seconds. Calculation of Results.-The specific gravities of methylamine and its solutions were obtained by dividing the weight of water required t o fill the cell t o the respective pointers a t 18' into the weight of methylamine or its solutions required t o fill the cell t o the same pointer without the introduction of any corrections. The viscosities were calculated by means < of the well-known formula
in which So and 7, and to represent respectively the specific gravity, viscosity and time of outflow of water and S, 71 and t the corresponding constants for the second liquid.
Experimental Data The results obtained in this investigation are given in the following tables, in which 'p. IO-^ represents the dilution in liters per mol., D the density and the fluidity. Potassium Iodide.-The salt used for the following measurements was from an analyzed specimen by J . T. Baker, which received no treatment before use other than thorough desiccation.- Potassium iodide dissolves in methylamine t o a clear and colorless solution.
+
Jour. Am. Chem. SOC.,29,
IO
(1907).
Fred F . Fitzgerald
650
I
-3.328
I 0.7335 I I1 0.8670 0.7865 0 7537 I 111
1
___
_.-_______
_ _ _ _
363.2 If':?
227.7 304.3 343.3 ___
18.88 196.6 368.8 546.2
1
IV 0.7109 0.6995 0.6947
1
0.6778 0.6889 0.6876
391.6 405.2 412.0
'
1
v 423.0 421.0 421.7
I 10.09 18.86 28.01 0.9596 1,795
3.023 5.655 8.396
I I ~
1
0.8658 0.7839
205.0 292.7
0.751' I 0.7206 I
334.7 373.7 388.6
0.7101
I
I
0.6934 1 4 1 4 . 2
V 22.17 I 0.7013 411.6 _ 61.57 _ _ ~ 1 _0.6937 _ _ 1418.0 VI 115.5 i 0.6939 1420.0 0.6908 423.5 _ _320 _ _ _ _8_ _ VI1 _ _ -~ - _ _ - _ _ 0.2800 1.261 29.78 0.5237 1.043 111.06 180.8 0.7778 o.goro
'
Metamethoxybenzenesulfonarnide. -This substance, prepared by E. C. Franklin,I is soluble in methylamine, producing a clear colorless solution. J. H. U . Dissertation, 1894.
Electrical Conductance of Solutions
. .
0.7868 1.471 2.184
I
-
0.8301 0.7674 0.7386
I
177.6 280.2
314.6
1
2.962 5.540 8.226
1I
0.7288 0.7101 0.7006
65 1
,
351.3 380.3 400.1
Fred F. Fitzgerald
652
methylamine, but less soluble than in liquid ammonia. concentrated solutions are surprisingly fluid. p.10-3
0.9235 I . 728 2.565
D
1 + 1
0.9274 0.8148 0.7729
2933 353.7 372.2
'1
I 1
-
9.10-3
1
I
133.0 369.6
,
I
1
-~ ..
+
I
13.92 26.05 38 68
0.6928 ' 416.6 0.6949 419.6 0.6889 1 423.1' 111 0,6933 I 422.8 0.6874 I 425.4
1
'
17.36 32.48 48.22
'
The
1.502
2.810 4.173
1
0.7778 0.7387 0.7207
1
282.0 339.1 371.3
I!
SodizLm Nitrate.-This specimen of Kahlbaum received no treatment before use other than thorough drying. p. IO-^
y2.582 :;6 4.426 8.280 12.29
I
1
~
'
1 ,
'1
D~ ~ ~ _1 _ _ _ __ _ ___.
I 0.7711 0.7300 0.7139 I1 0.6960 0.7036 0.6969
~
1
I
267.2 337.9 365.0
1 1
389.4 I 402.4 410.01
IO-^
22.09
175.3 327.9 486.9
1 ~
____ D
I11 0.6939 IV 0.6908 0.6884 0.6873
i 1
415.9
422.2 420.0
423.7
Electrical Conductance of Solutions
653
Lithium Chloride.-For use in this experiment a sample of Kahlbaum's special salt was dissolved in water, precipitated by hydrochloric acid and dried by heating in a stream of gaseous hydrochloric acid. __ __ __~__~_~_~______~ __ _ ________ _ _ _ _ _ _ _ _ _ _ ~-_-~ _ _ _~ _~ _ I_ __-_.____
IO-^
0,4986 0,7404
D I ___ 1
I 0.7802 0.7530
1
1
+
,~ I
1
IO-^
_ _ _ _ ~
107.0 182.4
6.939 12.98
I
I
O
111 0.6961 0.6939
/
+
393.4 407.9
Tetramethylammonium iodide and trimethylsulf onium iodide are practically insoluble in methylamine. Liquid Ammonia Solutions It was not deemed desirable t o attempt the adaption of the apparatus used for measuring the fluidity of methylamine and its solutions t o the study of liquid ammonia. An entirely new form of viscosimeter was therefore constructed, a description of which, together with an account of the method of its manipulation, is given below. Since in this form of viscosimeter it was not possible t o combine specific gravity and viscosity measurements into one series of operations, the density determinations were made in a separate piece of apparatus shown in Fig. 8. The amounts of water required t o fill the Fig. 8 cell t o the four pointers a t 18' weighed in air were 4.897,8.948, 18.683 and 34.352 grams from which the respective volumes 4.903, 8.959, 18.705 and 34.393 cubic centimeters are calculated for the temperature -33.5O. The total volume of the cell was approximately 37. o cubic centimeters.
I'
Fred F . Fitzgerald
654
The Density of Liquid Ammonia.-For determining the density of the pure solvent the cell, with the side tube sealed off, was weighed, exhausted of its air content, then filled with to one of the four glass pointers, and ammonia at -33.5' after warming t o laboratory temperature, weighed with its contents of ammonia. The results obtained are given in the table in which the values given in the fourth column are obtained by simply dividing the apparent weights of ammonia required t o fill the cell to the respective pointers a t -33.5 O by the weight of water required to fill the cell t o the same pointer at 18'. I n column 5 are given the values for the true density of liquid ammonia a t -33.5 O referred to water a t 4O.
I 2
~
I
3
69.014 69.050 69 043 '
45 569 45 624 45 624 45 596 45.624 45 624 45 624 45.571 45.571 '
i
' '
'
6 7 8 9
I
1 1
58.376 58.378 51.666 48.907
' '
I
i 1
0.6819 0.6821 0.6819 0.6815 0.6820 0.6826 0.6827
0.6813 0.6813
i '
1
1
0.6821 0.6823 0.6821 0.6821 0,6825 0.6832 0 6833 0.6825 0.6836 '
The data of experiments I , 2 and 3 were obtained with the cell filled t o pointer 4 ; those under 4,5, 6 and 7 with the cell filled t o pointer 3 ; and those under 8 and 9 filled t o pointer 2 and I , respectively. Omitting determinations 8 and 9, for the reason t h a t they were made on small quantities of liquid, the mean of the seven remaining determinations is found to be 0.6825 for the liquid at its boiling point referred to water a t its maximum density. The mean of the uncorrected values is 0.6821, which in view of the variations among the individual determinations is practically identical with the corrected value. These results are in rather poor agreement with the value 0.6757 obtained by Lange,' but agree fairly well with the Zeit. angew. Cheni., 1899,2 7 5 .
Electrical Conductance of Solutions
655
results of Drewes' and Dieterici' t o the extent that whereas the data of Drewes and Dieterici between oo and IOO', the limits within which their measurements were confined, are approximately one percent higher than those obtained by Lange ; so also are the results recorded in this paper for - 3 3 . 5 O higher than Lange's value at the same temperature by an amount of the same order. Density 'of Liquid Ammonia Solutions.-The following procedure was followed in determining the density of liquid ammonia solutions: A weighed quantity of solute is introduced into the cell shown in Fig. 8, after which the tube is closed by sealing off the tubulure A before the blowpipe, and weighed together with the salt. After the solute has dissolved and the operator has satisfied himself of the homogeneity of the solution, the surface of the liquid is adjusted accurately to the glass pointer. The tube is then allowed t o come to laboratory temperature when it is weighed. The data for the calculation of the concentration and the specific gravity of the solution thus become known. More liquid is then distilled into the tube t o the points two, three and four. After the last pointer has been reached, the cell is emptied, a new neck is sealed on the tube A, when the apparatus is ready for a new series of measurements. I n the tables which follow are given under D the densities of the solutions of a number of salts in liquid ammonia at the respective dilutions given in the first column under the superscripture 'p . IO-^. The density values recorded are obtained by simply dividing the weights of water a t 18' required to fill the cell t o the respective pointers, into the weight of solution required t o fill the cell t o the same pointer a t -33.5O.
' Dissertation,
Hannover, 1903. Zeit. gesammt. Kolteind , 11, I (1904)
Fred F . Fitzgerald
656
-_
-
Potassium Iodide
Szmose
1
cp.~o-*
D
I 0.2255 0 ' 4709 0.8658
I . 2910
0.5821
0.9790 0.8441
I . 21.5
1I
2.235
1.054 0.8640 0.7814
11. 6.054 12.64 2 3 ' 25
I
0.7180 0.6984 0.6913
cu (NO,) 24"s I
I
0.9340
0,7559
I1
2.072
3.786 7,907 14.53
1
1 j
0.7144 0.6980 0.6907 0.6867
8.525 15.58 3 2 * 53 59.80
0.7012
0.6934 0.6873 0.6851
Siluev Iodide 1. 0.5406 0.9879 2.063 3.791
1 1
1.0780 0.8995 0.7865 0.7385
1
2.301 1,5740
1 I1
0.1305 0.2384 0,4978 ~-0.9152
1
1 . 1 1 ~
0.9185 -
111 2.531 4.625 9.656 17.75
0.7522 0.7152 0.7005
0.5072 1.059 1 ,947
I 0.7690 0.7277 0.6970 0.6946
0.2335
I
I . 0015
0.7108
I1 1
0.7927
I
Electrical Conductance of Solutions A i?ziiioniumBromide-(Continued)
65 7
___ ___
1
Silver Nitrate
I 1,356 2.478 5.175 9.515
V
.
0.2474 0.4520 0.9436 1.735
1
J
I I
_-__ 0.9875 0.8530 0.7654 0.7281
-__
1
li
12.87 23.53 49," 90.33
I1
'
0.7991 0.7474 0,7137 0.6994
I1
1
0.6925 0.6883 0.6846 0.6833
Fluidity of Liquid Ammonia Solutions.-The viscosimeter used in measuring the fluidity of liquid ammonia and its solutions and of sulphur dioxide is shown in Fig. 9. L is the Dewar thermostat vessel. The tubes for introducing and removing liquid ammonia and for the escape of ammonia gas from the thermostat are not shown in the figure. The elaborate devices used by Franklin and Cady' for maintaining constant temperatures in this bath were dispensed with and dependence placed upon the prqsence of platinum tetrahedra in the bottom of the bath t o prevent superheating. A series of determinations is carried out as follows: Starting with the clean, dry viscosimeter immersed in the thermostat as shown in the Fig. 9 figure, the first operation consists in introducing a weighed quantity of solute by means of a long-stemmed funnel through C into the body of the cell 1
Jour. Am. Chem. SOC.,26,499 (1904); Zeit. phys. Chem., 69, 278 (1909).
658
Fred F . Fitzgerald
J’J’’, after which C is closed with a cork stopper held in position by a metal cap screwed down over C. Ammonia is then distilled into the cell by way of N X F E H until the surface of the solution formed stands slightly above the tip of the glass pointer J. The final adjustment of the volume is accomplished by passing a current of pure, dry hydrogen gas through the solution by way of M X F E H D A. The commotion caused by the passage of the hydrogen ensures homogeneity of the solution and at the same time, volatilizing and carrying off ammonia, enables the operator to adjust the surface of the solution to the pointer J. The known volume of the cell together with the known quantity of solute introduced furnish the data for calculating the concentration of the solution. The next step is the determination of time of outflow of the viscosimeter. To this end E is closed and hydrogen pressure is brought t o bear on the surface of the solution in J J‘ by way of B D. Solution is thus forced up through the capillary tube and into the bulb K. As soon as the surface of the solution reaches a line somewhat above K, the stopcock D is closed and E is opened, thus bringing about equality of pressure in the two legs of the apparatus, and establishing the conditions required for determining the time of outflow which latter is recorded by means of a good stop-watch. A second dilution is made by distilling additional ammonia into the cell and adjusting the surface of the solution to the pointer J’ in the manner already described for pointer J. After emptying the cell until the surface of the solution reaches pointer J, readings of the time of outflow are again made. The cell is now emptied and washed clean preparatory to charging with a fresh solution. Operations t o this end are as follows: Hydrogen pressure is turned upon the surface of the solution through B D when, with stopcocks E and F set t o open through Y , the solution will be forced over into a suitable waste vessel. Stopcock D is then opened through A, and ammonia gas is run into the cell by way of N S F E, thus displacing the hydrogen. Closing D will determine the liquefaction of ammonia in the cell. This wash liquid is then
r-
Electrical Conductance of Solutions
659
removed after the manner described above. The washing is continued until the cell is free from solute, when the apparatus is in readiness for repeating the operations described with fresh solutions. Viscosimeter Constants.-The capacities of viscosimeter No. I at 18' are 14.83 and 31.83 grams of water, respectively, to pointers J and J', with the liquid standing at capillary height in the tube H,K, and 18.67 grams to pointer J with the tube H K E filled t o stopcock E This volume will be referred t o as volume Ja. The time of outflow of water at oo for mark J is 1 7 0 . 7 seconds; for mark Ja, 203.6 seconds. The glass pointer J of viscosimeter No. I was inadvertently broken off. The sealing in of a new pointer changed the value of mark J to 14.74. The cell thus repaired will be called viscosimeter No. 2 . The volumes of viscosimeter 3 t o mark J, Ja and J' a t 18' are 11 .05 cc., 14.66 cc., and 26.03 cc., respectively. The time of outflow of water a t oo for mark J is 244.4 seconds, for mark Ja, 284. Q seconds. Experimeiztal Results. -In the tables which follow are given the dilutions in liters per gram. molecule, the specific gravities-obtained by interpolation from the results recorded in earlier pages of this article- and the fluidities of the solutions under the respective superscriptures, q . 1 0 - ~ , D and +.
Fred F . Fitzgerald
660
FLUIDITIES OF LIQUIDAMMONIASOLUTIONS Silver Iodide Viscosimeter No.
Potassium Iodide Viscosimeter No. I
I 0.2319 0.4979
I I
~
1.275 0.963
1
69. I7 189.7
1
254.3 319.2 348.3 355.8 366.3 372.8
0 . I377 0.2956 0.5040
15.51
0.7275 0.709 0.6965 0.689
1.894 3.229 5 507 9 389 16.01 27.29 +
314.7
0.702
1.086
I . 109 2.380 4.058 6.918 11.80
20. I 1
746 0.710 0.697 0.692 0.687 0.684
0.7537 1.618 2.759
-
0*
*
274.4 328.5 347.4 359.7 367. I 371. 7
44.76 164.3 278.0. 321.4 345.0 360.0 367.2
0.985 0,970 0.730 0.708 0.695 0.690 0.686
25.42 45.12
0.6935 0.6895 0.685 0.683
I1
355.9 372.2 375.3 376.4
Viscosimeter No. 3
11
I . I11
108.6 195.9
Sucrose'
I 0.896 0.788 0.746 0.718
IO. I2 ~
0.7215 0.6900 0.6840 0.6820
/I 0.3035 0.6518
2.2275 1.4250 1.1175
Viscosimeter No. 3
TT
3.130 5.335 9.097
1
I
1
0.9120 0.792 0.747
,
1
127.2 235.5 287.7
A solution containing 7 4 . 2 grams in cc of solution '' pp/~ooo= 0.427" was so viscous t h a t the bulb K had not half emptied itself in four hours. l
IOO
Electrical Conductance of Solutions Il
__-
-___
-
I I O l ; ~ _ _ _ I1 I1 4.423 0.724 ' 313.4 9.497 ! 0.699 347.2 15.20 1 0.693 361.7 I1 27.63 , 0.688 368.3 y.10-8
66 I
D
___-
Ammoniunz Bromide Viscosimeter No. 2
I
1 ~
Urea Viscosimeter No.
__ 0.752 0.717
-i 1-~0.245
I
~i
'
I o.ggo 1 68.46 0.5295 1 0.836 1 185.8 0.9065 1 0.766 255.3 1.52 1 0.734 300.9 I
1
0.702
~
7,739 I
0.694 0.688 0.684 0.683 I1
0.685
372.1
11
_376.0 _ _ 11
~
Silvw Nitratc Viscosimeter No.
,
368.3
17.97 l~ 30.63 11
11
I
____-
I!
52.22
0.6940 0.6880 0.6860 0.6835
,,
1
363.4 368.3 371.4 374.0
