What is electroplating? Write down the procedure of electroplating.

Electroplating is the process of depositing a thin layer of metal onto the surface of an object using an electrical current. The metal is deposited from a solution containing its ions. Electroplating is commonly used to improve the appearance, prevent corrosion, reduce friction, or increase the hardness of the object being plated.

Procedure for Electroplating:

  1. Preparation of the Object (Substrate):

    • The object to be electroplated (called the substrate) is first cleaned to remove any dirt, grease, or oxide layer. This can be done by physical cleaning (abrasive cleaning) or chemical cleaning (using acid or alkali solutions).

  2. Preparation of Electrolyte Solution:

    • An electrolyte solution is prepared by dissolving the metal salt (such as copper sulfate for copper electroplating) in water. The metal ions in the solution will be reduced and deposited onto the object during electroplating.

  3. Setup of Electrolytic Cell:

    • The object to be electroplated is connected to the cathode (negative terminal) of a power supply.

    • A metal rod (anode), made of the metal to be plated (e.g., copper), is placed in the electrolyte solution and connected to the anode (positive terminal) of the power supply.

  4. Electroplating Process:

    • When current flows through the electrolyte solution, metal cations from the electrolyte are reduced at the cathode (the object being plated) and are deposited as a metal layer:

      Metal2+(aq)+2e−→Metal(s)

    • The metal at the anode dissolves to replenish the metal ions in the solution, maintaining the concentration of metal ions in the electrolyte.

  5. Post-Plating Treatment:

    • After the desired thickness of the metal layer is achieved, the object is removed from the electrolyte solution, rinsed, and sometimes polished or coated with additional layers for improved properties.

Example (Copper Electroplating):

  • The electrolyte for copper electroplating is copper sulfate (CuSO₄) solution.

  • The object to be plated (cathode) is connected to the negative terminal, and a copper anode (positive terminal) is used.

  • Copper ions (Cu²⁺) from the electrolyte are reduced at the cathode, and a copper layer is deposited on the object.

Related Questions:

  1. What is the principle of electroplating? How is electroplating of chromium carried out?
  2. How does calcium metal react with dilute H₂SO₄?
  3. How is electroplating of tin on steel carried out?
  4. In electroplating of chromium, which salt is used as an electrolyte?
  5. Find out the oxidation numbers of the underlined elements in the following compounds:
  6. How can a non-spontaneous reaction be carried out in an electrolytic cell? Discuss in detail.
  7. Discuss the electrolysis of water.
  8. Discuss the construction and working of a cell in which electricity is produced.
  9. How can we prepare NaOH on a commercial scale? Discuss its chemistry along with a diagram.
  10. Discuss the redox reaction taking place in the rusting of iron in detail.
  11. Discuss why galvanizing is considered better than tin plating.
  12. Choose Arrhenius acids from the following compounds: HF, NH₃, H₂SO₄, SO₂, H₂S, H₂O
  13. Which salt is formed when HCl reacts with BaCO₃?
  14. How will you justify that H₂SO₄ is a Bronsted-Lowry acid?
  15. Define oxidation in terms of electrons. Give an example.
  16. Define reduction in terms of loss or gain of oxygen or hydrogen. Give an example.
  17. What is the difference between valency and oxidation state?
  18. Differentiate between oxidizing and reducing agents.
  19. Differentiate between strong and weak electrolytes.
  20. Why is steel plated with nickel before the electroplating of chromium?