Faraday’s Laws of Electrolysis

Faraday’s First Law of Electrolysis
The mass of a substance deposited or liberated at any electrode is directly proportional to quantity of electric current passed.

If W grams of a substance is deposited or liberated on passing Q Coulomb of charge then :


and W = Z x Q

where Z is the proportionality constant and is called the Electrochemical Equivalent

Faraday’s Second Law of Electrolysis
When the same amount of charge is made to pass through any number of electrolytes, the mass of the substance liberated or deposited at the electrodes are directly proportional to their chemical equivalents.

Chemical equivalent = atomic mass / valence

m1/m2 = E1/E2

where m1 and m2 are the respective masses liberated or deposited on the electrodes
and E1 and E2 are the chemical equivalents of the substances liberated or deposited.