How many coulombs are required to discharge 1 mole of the following ions: Cu^2+, Na^+, Pb^2+. (1 mole of electrons = 96500 coulombs)
To solve this type of problem, first write the half-reaction that is taking place. Then look at the number of moles of electrons involved and then convert that to coulombs.
In the first case:
Cu = Cu^+2 + 2 e^-1 This means that two moles of electrons are produced when copper is oxidized to copper +2. Two moles of electrons is equal to 2 moles * 96500 Coulombs/mole = 193,000 C.
Na = Na^+1 + 1 e^-1 One mole of electrons is produced which is equal to 96,500 C
Pb = Pb ^+2 + 2 e^-1 Two moles of electrons, or 193,000 C