What is electrochemical cell in chemistry class 12th

 

⚡ What is an Electrochemical Cell in Chemistry?

An electrochemical cell is a device that converts chemical energy into electrical energy (or vice versa) through redox (oxidation-reduction) reactions.

🔹 Definition:

An electrochemical cell is a system where a redox reaction occurs in a way that allows the transfer of electrons through an external circuit, generating an electric current.

🔹 Types of Electrochemical Cells:

Type Purpose Example
Galvanic (Voltaic) Cell Converts chemical energy → electrical energy (spontaneous reaction) Daniel cell, batteries
Electrolytic Cell Converts electrical energy → chemical energy (non-spontaneous reaction) Electrolysis of water, electroplating

🔹 Components of an Electrochemical Cell:

  1. Two Electrodes:

    • Anode: Site of oxidation (loss of electrons)
    • Cathode: Site of reduction (gain of electrons)

  2. Electrolytes: Solutions that contain ions and allow charge flow.

  3. Salt Bridge (in galvanic cells): Maintains electrical neutrality by allowing ion flow between solutions.

  4. External Wire: Carries electrons from anode to cathode.

🔹 Example: Daniel Cell

Setup:
Zn | Zn²⁺ (1 M) || Cu²⁺ (1 M) | Cu

  • Anode (Zn):
    Zn → Zn²⁺ + 2e⁻ (oxidation)

  • Cathode (Cu):
    Cu²⁺ + 2e⁻ → Cu (reduction)

  • Electron Flow: From Zn to Cu through the wire

  • Salt Bridge: Balances charge by moving ions between solutions

🔹 Uses of Electrochemical Cells:

  • Batteries (dry cell, lead-acid, lithium-ion)
  • Electroplating
  • Electrolysis (e.g., of water or salt)
  • Measuring electrode potentials

Would you like a diagram or a Hindi explanation of this concept?

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