COMMUNICATIONS TO THE EDITOR
Aug., 1933
to within 0.05 mv. for two to four hours, followed by a slow drift. The micro results are as reproducible as with the macro technique, the average value being only 0.01 mv. less than that computed from the Harned and Wright empirical eq. (2); namely, for m = 0.01; E = 0.23549 v. HCI, M
Type
0 0.103 ,3454 .5109
Eo 01, mv.
{ [
0.23552 ,23545 ,23544
*
,01002 ,01008
{
,01006 .01006
,23550 ,23548
* *
( 0 01002
A
NDlO
0.07 .04 =t .03
.6925
f
,9240
.06 .03
1511
Molality HCI
Eo.o m mole/1000 g.
0.011182 ,010855 ,01192 ,013576 ,00880 ,01127 ,01018 ,008844 .009718 ,010446 .009991
0.23548 ,23541 ,23736 ,24604 ,24614 ,25301 ,25306 ,26173 ,26169 ,27190 ,27195 ( ,2752)
Eo.01m
moIe/LiLi.5 moles
(1 .0000) DEPARTMENT OF CHEMISTRY VICTORK. LA MER COLUMBIA UNIVERSITY MARIONH. ARMBRUSTER The measurements were made at 25" NEWYORKCITY B micro cells as described [La Mer RECEIVED MAY 23, 1935
0.23548 ,23541 ,23677 ,24409 .24419 .25016 ,25021 ,25770 ,25766 ,26685 ,26690 ( ,2700)
with Type and Armbruster, THISJOURNAL, 57, 1510 (1935)] where the reliability of the micro technique is established. In the last column of the table the e. m. f. is corTHE E. M. F. OF THE QUINHYDRONE ELECTRODE rected to exactly 0.01 mole H C 1 / 5 5 . 5 moles IN HEAVY WATER. THE ACIDIC DISSOCIATION solvent for purposes of comparison. The normal OF DEUTEROQUINOHE potential is 0.4774 volt, but in heavy water the Sir: value extrapolated linearly would be 0.5119 v. By measuring the e. m. f. of the cell if we make the highly plausible assumption that the activity coefficients in DzO and H20 are Ag, AgCl, HCl(0.01 M), Quinhydrone (Q.QH*),Pt (I) NDs0,the mole fraction of heavy water identical. corresponding to the processes was computed from density measurements using ZHCl(0.01 M) Q 2Ag(s) = ZAgCl(s) 4-QH2; EH(1) the formula of La Mer and Baker [ibid.,56, 2641 2DC1(0.01 M ) Q 2Ag(s) = ZAgCl(s) 4-QDz;ED( 2 ) (1934)]. Both curves deviate from linearity at when carried out in ordinary and heavy water, low DzO concentrations. Experiments are in we obtain the free energy of the exchange process progress to check the reliability of extrapolation. ZDCl(O.01M)+ QHZ = 2HC1(0.01 M) + QDz; ED - E H The investigation is being continued, using the (3) deuterium gas electrode to study the reaction, If we assume that the activity of the chloride QD2 Hz = QHz D2. ion is the same in both waters, equation (3) may DEPARTMENT OF CHEMISTRY VICTOR K. LA MER COLUMBIA UNIVERSITY SAMUEL KORMAN be considered as the difference of the dibasic NEW PORK CITY acid dissociations RECEIVED JULY22, 1935
+ + + +
+
QH2 = QQD2 = Q-
+ 2H+ (in HzO); Ka + 2 D + (in DzO); KD
(4) (5)
where KH, the average dissociation constant, equals K1Kz = (1.75 x 10-1°)(4 X 10-l2) = 2.64 X lo-" for ordinary water [S. E. Sheppard, Tr. Am. Electrochem. Soc., Preprint 39 (1921); La Mer and Parsons, J. B i d . Chem., 57, 613 (1923) I. Extrapolation to pure DzO indicates that E D - EH = 0.0345 v. Hence log KH/KD = 0.0345/0.05911 = 0.5837, or KH/KD = 3.54, a result which accords with the decrease in acidic dissociation of other weak acids in DzO; e. g., deutacetic acid [Lewis and Schutz, THISJOURNAL, 56, 1002 (1934)], chloroacetic acid [ibid., 56, 1913 (1934)].
+
THE OXIDATION AND REDUCTION OF DEHYDROANDROSTERONE
Sir: It has been shown by Gallagher and Koch
[ J . BWZ. Chem., 104, 611 (1934)] that highly active testicular extracts are sensitive to hydrogenion concentration, and show a decided decrease in their activity when boiled with alkalies, whereas active extracts obtained from male urine do not show this behavior. This fact strongly indicates that the active compound present in the testes is different in structure from that of androsterone. It is also known that this instability toward alkalies is a characteristic property of the corpus luteum hormone.
