Electrolysis with solutions
Electrons are pumped out of the silver metal in effect corroding it and releasing silver ions into the electrolyte solution.
Ag(s) => Ag+(aq)+ e
Ag+(aq)+ e =>Ag(s)
The ions that
migrate are not always the ones that have just being released from the
silver metal but may be any silver ion in the electrolyte. The ions that
are released from the silver metal just replace the ions that have been
taken out of the solution. A constant silver ion concentration is maintained.
Give the polarity
and the reaction that occurs at the cathode.
Electroplating is not as simple as the animation above shows. If we were to coat a piece of iron in this manner a loose black sludge would develop. In practice the voltage, current, temperature and electrolyte are carefully controlled.
Looking at the animation above it is easy to see the relationship between number of atoms of silver deposited and the number of electrons that pass through the circuit.
This relationship is very important and leads us into the next chapter where we can calculate the mass of metal deposited given the current supplied.