Faraday’s First Law Made Simple: The Only Electrolysis Formula You Need for NEET

Doing a last-minute electrochemistry revision? Don’t skip Faraday’s First Law. It’s one of the most frequently tested electrolysis concepts, and understanding it can make tricky numericals feel surprisingly simple. 

Here is the only tab you’ll need to open for Faraday’s first law of electrolysis for NEET. 

Faraday’s First Law of Electrolysis Explained

Faraday’s first law of electrolysis states that the mass of a substance deposited or liberated at an electrode during electrolysis is directly proportional to the quantity of electricity passed through the electrolyte.

m∝Q 

• m = mass deposited or liberated
• Q = charge passed through the electrolyte

The Electrolysis Process Explained

Electrolysis is a process in which electrical energy is used to drive a non-spontaneous chemical reaction. When an electric current passes through an electrolyte, ions move towards the electrodes and undergo chemical changes.

For example:

Cu2+2e−→Cu

Copper ions gain electrons and get deposited as copper metal.

This deposition can be measured as mass, which is exactly what Faraday’s law helps us calculate.

Faraday’s First Law Formula

Since charge is given by: 

Q = It 

where:

• I = current
• t = time

Faraday’s First Law can be written as:

m = ZQ 

Or 

m = ZIt

Here, Z is called the electrochemical equivalent.

What Is Electrochemical Equivalent (Z)?

The electrochemical equivalent (ECE) is the mass of a substance deposited when one coulomb of charge passes through the electrolyte.

Z = M/nF

where:

• M = molar mass
• n = number of electrons transferred
• F = Faraday constant

This equation frequently appears in Faraday’s first law derivation and numerical questions.

What Is One Faraday?

A very important exam fact:

1F = 96500 Coulombs

One Faraday represents the charge carried by one mole of electrons.

Faraday’s First Law Explained with Examples

Consider copper electrolysis:

Cu2++2e−→Cu 

Since two electrons are required to deposit one mole of copper:

• 1 mole Cu requires 2 Faradays
• 0.5 mole Cu requires 1 Faraday

This shortcut can save valuable exam time and is commonly used in Faraday’s first law numericals.

One More Concept You Should Know

While studying Faraday’s laws of electrolysis, students usually learn two laws together.

The second law states that when the same quantity of electricity passes through different electrolytes, the masses deposited are proportional to their equivalent masses.

For NEET, most direct numerical questions are still based on the first law, but it is useful to remember the existence of the second law.

Practice Previous Year Questions

The best way to master electrolysis is by solving actual exam questions.

For Faraday’s first law PYQ practice, access our curated collection here:

[PYQ Link]

Faraday First Law Summary Notes

Here are your Faraday first law summary notes:

• Mass deposited is directly proportional to charge passed.
• m∝Q
• Q=It
• m=ZQ
• m=ZIt
• Z=MnF
• 1F=96500 coulombs.
• One Faraday represents one mole of electrons.

These points work perfectly as Faraday’s first law short notes.

Conclusion

Need one final revision of Faraday’s first law of electrolysis, Re-NEET 2026, before moving on? Check out our detailed video explanation here. We cover the complete concept with examples and give you a quick refresher during your Faraday first law one-shot revision. 

Most of Faraday’s first law important questions and Faraday’s first law MCQs are built around these core ideas explained here on this page and the video. Once these are clear, electrolysis becomes one of the most scoring parts of electrochemistry.

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