Why do different metals develop different voltages across their electrode surfaces, in contact with the same electrolyte? What other factors besides electrode material affect electrode potentials?
Picture the surface of a metal electrode in contact with an electrolyte at left. A voltage develops across the metal/solution interface because charges are distributed differently on either side of the interface. Suppose some of the metal cations move from the metal side to the solution side. If the metal is zinc, we can write an equation to describe this process. Zn(s) = Zn2+(aq) + 2e- Two electrons are left behind in the metal; the charge on the metal strip becomes more negative. The solution becomes more positive. The voltage between the solution and metal will increase because the difference in charge will increase. If the electrons are removed somehow, the process can continue, and you’ll see the zinc strip gradually dissolve. The reverse process also occurs. You can have metal cations move from the solution to the metal.This process could be described as Zn2+(aq) + 2e- = Zn(s) If more electrons are supplied, this process can continue, and most of the zinc ions in solution will en
