The Limitations of Faraday’s Second Law of Electrolysis: Exploring its Constraints and Implications

Faraday’s laws of electrolysis, formulated by the renowned scientist Michael Faraday in the 19th century, have been instrumental in our understanding of electrochemistry. The second law, in particular, states that the amount of substance deposited or liberated at any electrode during electrolysis is directly proportional to the quantity of electricity passed through the electrolyte. However, like any scientific law, Faraday’s second law of electrolysis has its limitations and constraints. This article aims to explore these limitations and their implications in the field of electrochemistry.

Understanding Faraday’s Second Law of Electrolysis

Before delving into the limitations, it’s crucial to understand the law itself. Faraday’s second law of electrolysis can be stated as follows: When the same quantity of electricity is passed through several electrolytes, the amount of substances deposited at the electrodes is directly proportional to their respective chemical equivalent or equivalent weight.

Limitations of Faraday’s Second Law

Despite its wide acceptance and application, Faraday’s second law of electrolysis is not without its limitations. These limitations can be broadly categorized into three main areas:

  • Non-ideal behavior of electrolytes: The law assumes that all electrolytes behave ideally, which is not always the case. Real electrolytes often deviate from ideal behavior due to factors such as concentration, temperature, and pressure.

  • Side reactions: Faraday’s second law does not account for side reactions that may occur during electrolysis. These side reactions can significantly affect the amount of substance deposited at the electrodes.

  • Overpotential: The law does not consider the overpotential, which is the extra potential required to drive the reaction at a faster rate. Overpotential can affect the efficiency of electrolysis and the amount of substance deposited.

Implications of these Limitations

The limitations of Faraday’s second law have significant implications in the field of electrochemistry. For instance, they highlight the need for more accurate models and theories that can account for non-ideal behavior, side reactions, and overpotential. These limitations also underscore the importance of experimental verification and adjustment of theoretical predictions.


Despite its limitations, Faraday’s second law of electrolysis remains a cornerstone in the field of electrochemistry. It provides a fundamental understanding of how electrolysis works and serves as a starting point for more complex theories and models. However, it’s essential to be aware of its limitations and their implications to ensure accurate predictions and efficient electrolysis processes.