It states that “the amount of any substance that is deposited or liberated at an electrode is directly proportional to the quantity of electricity passing through the electrolytic cell”.
The amount of electricity means quantity of change (Q) in coulombs. If I is the current in amperes (A) and t is the time in seconds, then Q = I t.
It states that “when a given quantity of electricity is passed through different electrolytes, the amounts of different substances produced at the electrodes are directly proportional to the respective equivalent weights”.Thus the electrochemical equivalent (Z) of an element is directly proportional to its equivalent weight (E),
i,e.,E = FZ
Where F is again a proportionally constant and has been found to be 96540 coulombs. It is called faraday. Thus E = 96540 Z
Therefore , when 96540 ( or roughly 96500) coulombs of electricity is passed through an electrolyte, one gram equivalent of its ions is deposited at the respective electrode. This quantity of electricity which liberates one gram equivalent of each element is called one faraday and is denoted by F.
1 Faraday = 96500 Coulombs