—— pe 
—— 
155 
the case the metal is immersed in a perfectly pure solvent, may 
be easily derived. 
From the equation: 
MM" + v6 
follows that the concentration of the electrons will be rv times as 
great as that of the metal ions, so that: 
toy)» (My) : 
If we now substitute this value for (97) in equation (11), we get: 
B KE 
EE In A ee € 
Er | n ae v In >| (13) 
This equation expresses that the potential difference between a v-valent 
metal and a pure solvent is entirely determined by the valency and 
by the solubility of the metal ions and electrons. ') 
4. Polarisation and passivity of a metal that contains 
only one kind of metal ions. 
Now the question can be answered whether it is possible that a 
meta!, in which in case of unary behaviour the internal equilibrium 
v. 
M2M” + 6 
prevails, can be polarized resp. made passive. 
To answer this question we start from our equations (6) and (7), 
‘from which follows that 
_ (i) _ (KOs) 
Kip. AL) (O1) 
or 
AGE ARD NOR eee 
(M7) (01) 
As was already stated in the foregoing communication equations 
(6) and (7) hold generally, hence also when the metal is not in 
internal equilibrium. 
When it is asked how in equations (6) and (7) the fact of the 
internal equilibrium expresses itself, the answer is, in the constancy 
of the concentrations (MS) and (Os). If there is no internal equili- 
brium, then these are not the equilibrium concentrations, but the 
equations (6) and (7) hold nevertheless, and also (14) derived from them. 
1) Of course this potential difference can only be determined after the metal and 
the solvent have been made perfectly free from gas. 
