What is Galvanic cell class 12th chemistry

 

🔋 What is a Galvanic Cell in Chemistry? (Class 12 – CBSE/NCERT)

A Galvanic cell (also called Voltaic cell) is a type of electrochemical cell that converts chemical energy into electrical energy using a spontaneous redox reaction.

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📘 Definition:

A Galvanic cell is a device in which a spontaneous redox reaction occurs in two separate half-cells and generates electric current.

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⚙️ Working Principle:

• Based on redox reaction (oxidation and reduction)
• Electrons flow from the anode (oxidation site) to the cathode (reduction site) through an external wire.

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🔹 Main Components of Galvanic Cell:

Component	Function
Anode	Where oxidation occurs (loss of e⁻)
Cathode	Where reduction occurs (gain of e⁻)
Electrolyte	Provides ions to complete the circuit
Salt Bridge	Maintains charge balance between solutions
External Wire	Transfers electrons from anode to cathode

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🔋 Example: Daniel Cell

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

• Anode (Zinc rod):
  Zn → Zn²⁺ + 2e⁻
  (Oxidation)

• Cathode (Copper rod):
  Cu²⁺ + 2e⁻ → Cu
  (Reduction)

• Electron Flow:
  From zinc to copper through wire.

• Salt Bridge:
  Typically contains KCl or NaNO₃; it prevents charge buildup by allowing ions to move.

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⚡ Cell Representation (Cell Notation):

\text{Zn (s)} \ | \ \text{Zn}^{2+} (1M) \ || \ \text{Cu}^{2+} (1M) \ | \ \text{Cu (s)}

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📏 Cell Potential Formula:

E^\circ_{\text{cell}} = E^\circ_{\text{cathode}} - E^\circ_{\text{anode}}

For Daniel Cell:

E^\circ = 0.34\,V - (-0.76\,V) = 1.10\,V

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📚 Uses of Galvanic Cells:

• Used in batteries (dry cell, mercury cell)
• Portable energy sources
• Electrochemical studies

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