Faraday’s Laws of Electrolysis
Michael Faraday formulated two laws that govern the process of electrolysis, providing a quantitative foundation for understanding how electrolysis works in practice.
First Law
The First Law of Electrolysis states that the mass of the substance deposited or liberated at an electrode during electrolysis is directly proportional to the total electric charge (quantity of electricity) that passes through the electrolyte. This relationship can be expressed mathematically as:
m ∝ Q
where m is the mass of the substance, and Q is the quantity of electricity in coulombs. This law establishes that the greater the flow of electricity, the more mass is deposited or liberated at the electrodes.
Second Law
The Second Law of Electrolysis further elaborates that when the same quantity of electricity passes through different electrolytes, the masses of substances deposited are proportional to their respective chemical equivalent weights (or valencies). This can be formulated as:
m₁/m₂ = E₁/E₂
where m₁ and m₂ are the masses of the different substances deposited, and E₁ and E₂ are their equivalent weights. This law helps in predicting the outcome of electrolysis when multiple substances are involved, as it outlines that the amount of substance varies depending on its chemical equivalence.
Together, these laws are crucial for applications in electroplating, metal extraction, and other industrial processes that utilize electrolysis, highlighting their importance in both theoretical and practical chemistry.