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A topic from the subject of Electrolysis in Chemistry.

  • 10 months ago
  • 3 min read
Faraday's Laws of Electrolysis
Introduction
Electrolysis is the process of using an electrical current to drive a chemical reaction. Faraday's Laws of Electrolysis, discovered by Michael Faraday in the early 19th century, describe the quantitative relationship between the amount of electricity passed through an electrolytic cell and the amount of chemical change that occurs.
Basic Concepts
Electrolytic Cell: A device consisting of two electrodes (cathode and anode) immersed in an electrolyte solution, through which an electric current is passed. Electrolyte: A substance that contains ions and allows electricity to flow through it.
Electrodes: Conductors through which electricity enters and leaves the electrolytic cell. Cathode: Electrode where reduction occurs (negative electrode).
* Anode: Electrode where oxidation occurs (positive electrode).
Equipment and Techniques
Power Supply: Provides a constant voltage or current to the cell. Electrodes: Inert materials (e.g., graphite, platinum) that do not participate in the electrochemical reactions.
Voltmeter: Measures the voltage across the cell. Ammeter: Measures the current passing through the cell.
* Electroanalytical Balance: Used to accurately measure the mass of electrodes before and after electrolysis.
Types of Experiments
Quantitative Analysis: Determining the amount of a substance in a solution by measuring the mass of metal deposited during electrolysis (gravimetric analysis). Electroplating: Coating an object with a metal by electrodeposition.
* Electrosynthesis: Producing chemical compounds by electrolysis.
Data Analysis
Faraday's Laws of Electrolysis relate the amount of electricity (current) passed through an electrolytic cell to the amount of chemical change:
* Faraday's First Law: The mass (m) of a substance deposited or dissolved during electrolysis is directly proportional to the amount of charge (Q) passed through the cell: m = ZQ/F
- Z: Electrochemical equivalent (grams deposited per coulomb)
- F: Faraday constant (96,485 coulombs per mole of electrons)
* Faraday's Second Law: When the same amount of electricity is passed through different electrolytic cells, the masses of different substances deposited or dissolved are directly proportional to their respective electrochemical equivalents: m1/Z1 = m2/Z2 = m3/Z3
Applications
Electrorefining: Purifying metals by electrolysis. Electroplating: Coating surfaces for protection or decoration.
Electrosynthesis: Producing chemicals such as hydrogen and chlorine. Quantitative Chemical Analysis: Determining the concentration of ions in solution.
Conclusion
Faraday's Laws of Electrolysis are fundamental principles that govern the quantitative aspects of electrochemical reactions. They provide a basis for understanding and harnessing the power of electrolysis for various industrial and analytical applications.
Faraday's Laws of Electrolysis

Faraday's First Law of Electrolysis (Law of Mass): The mass of a substance deposited or liberated at an electrode during electrolysis is directly proportional to the amount of charge passing through the circuit.


Faraday's Second Law of Electrolysis (Law of Equivalents): When the same amount of charge passes through different electrolytic solutions, the mass of the substance liberated at each electrode is directly proportional to its electrochemical equivalent.


Key Points:

  • Electrolysis involves the decomposition of a compound by passing an electric current through it.
  • Electrolytes are substances that can conduct electricity when dissolved in water or melted.
  • Electrolysis occurs in electrolytic cells, where electrodes are connected to a source of electricity.
  • Cations (positively charged ions) move to the cathode (negatively charged electrode), where they reduce.
  • Anions (negatively charged ions) move to the anode (positively charged electrode), where they oxidize.
  • The electrochemical equivalent of a substance is the mass of the substance deposited or liberated by 1 coulomb of charge.
  • Faraday's laws provide a quantitative relationship between the amount of charge passed through an electrolytic cell and the mass of substance produced.

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