Faraday’s Laws of Electrolysis

The amount of gas released is determined by the electrode and electrolyte used, as well as the amount of electricity passed through the solution, among other factors.

Faraday’s laws of electrolysis were developed from Michael Faraday’s electrochemical research in 1833. The laws demonstrate a quantitative relationship between the substance deposited between the electrodes and the amount of electric charge or energy transferred.

Faraday’s Law Of Electrolysis

Michael Faraday (1833) conducted extensive research into the phenomenon of electrolysis, establishing a relationship between the amount of product liberated at the electrode and the amount of electricity passed through the solution to take out the electrolysis. He developed important electrolysis-related quantitative laws. Faraday’s laws of electrolysis are the most well-known of the laws.

What is Electrolysis ?

The process of electrolysis involves converting electrical energy into chemical energy. Electrolysis is the chemical deposition of an electrolyte caused by the passage of electricity through its molten or dissolved state. The substance to be transformed could be the electrode, the solution, or it could be dissolved in it. The cathode receives electric current (i.e., electrons), solution components travel to this electrode, combine with the electrons, and transform (reduced).

Look at the example where the Electrodes are immersed in a Sodium Chloride aqueous solution. When electric current is passed through a solution of sodium chloride, hydrogen gas is produced at the negative electrode, and chloride gas is oxidised to chlorine at the positive electrode.

• Reaction at cathode 

H2O + 2e– → H2 + 2OH–

Reaction at Anode 

Cl– → ½ Cl2 + 1e–

• Overall Reaction 

NaCl + H2O → Na+ + OH– + H2 + ½ Cl2

Mechanism Of Electrolysis :

An electrolytic cell is the device in which the electrolysis process is carried out. It is a device which has positive and negative electrodes that are held apart and dipped into a solution containing positively and negatively charged ions. The theory of ionisation can be used to explain the process of electrolysis. Cations refer to positively charged ions, while anions refer to negatively charged ions.

In an aqueous solution, the ions are free to move around. The ions respond to the applied potential difference when an electric current is passed through the solution, and their movement is directed towards the oppositely charged electrodes. Cations gravitate toward the negatively charged electrode (cathode), while anion gravitates toward the positively charged electrode (anode).

The formation of products at each electrode is caused by oxidation, electron loss at the anode, and electron reduction gain at the cathode.

Faraday’s First Law Of Electrolysis :

The amount of electricity passed through the electrolyte is directly proportional to the mass of any substance deposited or liberated at an electrode, according to Faraday’s first law of electrolysis.

m ∝ Q     m → Mass and Q → Charge

⇒ m= ZQ

⇒ m/Q= Z

Z → Constant of proportionality, the mass of the substance deposited/liberated per unit charge also known as electrochemical equivalent.

Faraday’s Second Law Of Electrolysis :

According to this law, when the same amount of electricity is passed through a series of electrolytes, the electrochemical equivalence is proportional to the masses of the substance liberated at the electrode. Divide the atomic mass of a metal by the number of electrons required to reduce its cation to get its electrochemical equivalent.

m ∝ E

⇒ E = molar mass/ Valency 

⇒ Z1:Z2:Z3:Z4…… = E1:E2:E3:E4….

Electrochemical Equivalent :

Faraday’s laws of electrolysis can be used to calculate a substance’s chemical equivalent or equivalent weight, which is defined as the weight of that substance that will combine with or displace the unit weight of hydrogen. As a result, unity is the chemical equivalent of hydrogen. Because a substance’s valency is equal to the number of hydrogen atoms it can replace or combine with, a substance’s chemical equivalent can be defined as the ratio of its atomic weight to its valency.

Z = Atomic weight/Valency

Application Of Faraday’s Law Of Electrolysis :

1. The estimation of equivalent masses of elements can be found by Faraday laws.
2. Non-metals such as hydrogen, fluorine and chlorine are obtained using the Laws of Electrolysis.
3. They are also used in Electron Metallurgy to retrieve metals such as sodium and potassium.
4. Electrolysis is used to carry out the processes of electroplating and electro-refining metals.
5. Renewable electricity can be achieved using electrolysis.

Conclusion

Michael Faraday’s electrochemical research in 1833 led to the development of Faraday’s laws of electrolysis, which show a quantitative relationship between the amount of electric charge or energy transferred and the substance deposited between the electrodes.

Electrolysis is the transformation of electrical energy into chemical energy. As per Faraday’s first law of electrolysis, the mass of any substance deposited or liberated at an electrode is directly proportional to the amount of electricity passed through the electrolyte. The electrochemical equivalence is proportional to the masses of the substance liberated at the electrode, according to this law, when the same amount of electricity is passed through a series of electrolytes is Faraday’s second law.