A Comprehensive Treatise on Inorganic and Theoretical Chemistry

PLATINUM 111
of chlorine in hydrochloric acid. A. Coehn and Y. Osaka found that with a soln. of
potassium hydroxide, cooled by a freezing mixture, much ozone is evolved with a
platinum anode at 3 volts. W. Kettembeil observed a break in the decomposition
curve at 1*32 volts. G. Armstrong and co-workers studied the subject. A. Coehn
and St. Jahn studied the phenomenon with soln. sat. with carbon dioxide ;
W. Kettembeil, with soln. of alkaline earth chlorides ; and B. Kamiensky, the
increased negative charge of a platinum electrode in a soln. of potassium chloride in
the presence of potassium xanthate.
The deposition potential of copper, silver, gold, zinc, cadmium, and iron on
platinum was studied by A. Coehn ; of lead dioxide, by K. Elbs and J. Forssell ;
of nickel, by G. Cofifetti and F. Forster ; and of platinum, by G. Bodlander,
B. Neumann, and J. Wagner. B. Bruzs studied the separation of hydrogen, oxygen,
and silver at bright platinum electrodes. G. Grube and co-workers observed that
in cone, hydrochloric acid, electrodeposited platinum dissolves anodically more
rapidly than rolled sheet. The dissolution of active platinum begins when .E=I
volt, and chlorine begins to be evolved at the passive pole at 1*2 to 1*4 volts.
Platinum can be transferred electrolytically from anode to cathode in M-H2PtCl6
in 5iV-HCl at 75°. With low current densities, the platinum dissolves at the anode
as Pt , but with high current densities, part dissolves as Pt"*. B. Kabanov
and A. Frumkin studied the bubble formation on platinum electrodes ;
M. O. Kharmadaryan and B. I. Pervuschin, moving electrodes ; and M. O. Charmandarian
and B. J. Pervuschin, N. Thon, K. Gostkowsky, T. Malarsky and
K. Gostkowsky, A. Coehn and O. Schafmeister, and S. Procopiu, the electrokinetic
potential.
N. Gautherot, 11 and P. Sue observed that if platinum wires which have been used
as electrodes in a soln. of salt, be put under and over the tongue, with the
wires in contact, the taste alters owing, it was suggested, to the electrolysis
of the water. The polarization of platinum cathodes in dil. sulphuric acid was
observed by A. C. Becquerel, G. Bird, E. du Bois-Reymond, A. Crova, G. T. Fechner,
C. Fromme, J. M. Gaugain, J. Harty, H. von Helmholtz, F. C. Henrici, G. Jones
and S. M. Christian, M. Krieg, P. L. Marechaux, E. Pirani, J. C. Poggendorff,
F. M. Raoult, C. F. Sehonbein, H. Schroder, E. I. Spitalsky and V. V. Picheta,
F. Streintz, P. G. Tait, P. S. Tutundzic, E. Warburg, and J. C. von Yelin.
M. Berthelot, J. A. V. Butler and G. Armstrong, H. Fricke, A. N. Frumkin and
A. Shluigin, C. M. Gordon, W. T. Heys, E. Merritt, N. I. NekrassofT, A. V. Pamfiloff
and O. S. Fedorova, E. Rothe, I. Slendyk, O. Stelling, I. Wolff, and E. E. Zimmerman
attributed the cathodic polarization of platinum to the formation of hydrides ;
and in the case of the anode, E. Rothe attributed the result to the formation of
platinum oxides. H. Edier and C. A. Knorr observed that adsorbed hydrogen
greatly influences the current-voltage curves of platinum electrodes in benzene.
F. Richarz observed that the formation of persulphuric acid, ozone, or hydrogen
dioxide exercised no influence on the polarization of platinum in dil. sulphuric acid.
The maximum polarization of platinum was found by W. Hallock to be 1-95 volts ;
E. Pirani gave 2-21 to 2-29 volts ; C. Wheatstone, 2-23 volts ; J. F. Daniell, 2-49
to 2-857 volts ; H. Buff, 2-56 volts ; J. C. Poggendorff, 2-33 volts ; A. F. Svanberg,
2-31 volts ; and F. Richarz, 2-5 volts. The average for dil. sulphuric acid is near
2-8 volts. Observations on the subject were made by A. Wullner and K. R. Koch,
J. IL. Kassner and co-workers, C. B. Jolliffe, M. Wien, J. B. Henderson, F. Exner,
W. Beetz, N. Nekrassoff, J. Parnell, P. G. Tait, F. Kruger, and F. M. Raoult.
V. Karpen studied the polarization in a soln. of potassium iodide and iodine ; and
W. H. Hunter and L. F. Stone, inorganic depolarizers.
R. Tholdte found the polarization in 10 per cent, sulphuric acid with feeble
strength of current, is approximately doubled when the strength of the current is
doubled, and with currents of greater strength, the increase is smaller, and
approaches a constant value. The subject was studied by F. Richarz, H. von Helmholtz,
A. W. Witkowsky, A. Bartoli, A. Bartoli and G. Poloni, H. Buff, J. A. Fleming,