guy - 14-1-2006 at 16:03
I'm sure this is a very easy problem but I can't figure it out. How does a voltaic pile work? Different metals are stacked alternatley with an
electrolyte in between. Say zinc and copper are used and NaCl is the electrolyte. How can a currnet be produced from Zn and Cu?? Only from Zn and
Cu++ right? Unless maybe salt speeds up oxidation of Cu to CuO and that is reduced?
12AX7 - 14-1-2006 at 16:43
Nope, the copper is just present as an inert electrode. It can be made pretty thin. Zinc is where the energy is at.
What you get is Zn + 2H2O > Zn(OH)2 + H2, the H2 gas bubbles off (if you add the right ingredient, MnO2 for example, you can get extra voltage from
the H2 gas, which is a fuel gas after all; "dry cells" use this very method). Electrons are of course produced as the zinc oxidizes, according to the
oxidation potential of zinc: about 3/4 volt per cell.
The NaCl is also inert, providing ions for conductivity. It would work with pure water, but it ain't very conductive 
Tim