1488 
from left to right. As the hydrogen then continually escapes, it 
will continue till the metal has entirely disappeared. 
In this way we come to the conclusion that the metals which act 
most strongly on water, are the metals with relatively great solubility 
product. 
c. Dissolving of metals in acids. Wf we now consider the phe- 
nomenon that some metals give hydrogen generation with solutions 
of acids as HCl, H, SO,, and others do not, we see in the light 
of these considerations that this phenomenon is entirely controlled 
by the equilibria: 
MME DO vee set spas, ae) 
and::2 Os DUS SH es Cale NS) 
from which we see that the metals with a relatively large solubility 
product will generate hydrogen, whereas the other metals do not 
do so. Metals as copper and silver ete. or in other words the noble 
metals, do not dissolve, because they have a too small solubility 
product. 
d. Dissolving of metals in the solution of a mixture of a ferro- 
and a fervisalt. 
We can now easily give an explanation of the different conduct 
of the metals with respect to a solution of a mixture of a ferro- 
and a ferrisalt. In this case we have to consider besides the metal 
ionisation equilibrium : 
MME DO on oe Taa var ee 
also the equilibrium : 
Pe Zet nme gd ene RE 
If the eleetron-concentration of the equilibrium (9) in the solution 
under consideration is greater than that which corresponds with 
the solubility product of the metal, the electrons from the solution 
pass into the metal, and at the same time the ionisation equilibrium 
(la) shifts from right to left both in the metal and in the solution, 
and metal deposits from the solution. The metals that behave thus 
are, of course, again metals with a small solubility product, hence 
they behave with respect to the said solution of a mixture of ferro- 
and ferrisalts as an unassailable electrode. 
If on the other hand the metal possesses a relatively large solu- 
bility product, electrons will be withdrawn to the equilibrium (1a) 
both in the solution and in the metal, and the metal goes into 
solution, the conversion represented by equation (9) proceeding from 
right to left, in which the ferri-salt is therefore reduced to ferro-salt. 
This takes place inter alia when M is the metal Zr. 
