Faraday Law of Electrolysis in Chemistry

Faraday Law of Electrolysis:

Faraday’s First Law of Electrolysis:

The amount of ions discharged or dissolved from an electrolyte at each electrode is directly proportional to the quantity of electricity passing through the electrolyte.


W ∝ Q

Where W = mass of ions liberated
Q = quantity of electricity passed through the electrolyte in the coulomb.
But Q = c x t = current in amp x time in sec.

W ∝ c x t
or, W = Z x ct

Where Z = constant is known as the electro-chemical equivalent (ECE) of the ion deposited.

Faraday’s Second Law of Electrolysis:

When the same quantity of electricity is passed through different electrolytes, the weights of different substances deposited or dissolved at the electrodes are directly proportional to their chemical equivalents.

Let W1 and W2 are the weights of two elements deposited by passing the same quantity (Q coulomb) of electricity through their salt solutions and E1 and E2 are their respective equivalent weights, then W1 / W2 = E1 / E2 i.e, W ∝ E.