Galvanic vs Electrolytic Cell - NEET Notes, Formula & Common Mistakes
Electrochemistry·2 min read·NEET 2026
What NEET Asks
Identify and differentiate between galvanic and electrolytic cells based on energy conversion, spontaneity, and electrode polarity.
Predict the nature of reactions (oxidation/reduction) at specific electrodes.
Questions often involve scenario-based identification or direct comparison of properties.
Key Points
Galvanic (Voltaic) Cell: Converts chemical energy (from spontaneous redox) into electrical energy. ΔG < 0.
Electrolytic Cell: Converts electrical energy into chemical energy (drives non-spontaneous redox). Requires external power. ΔG > 0.
: Site of in cells. In galvanic, it's the electrode. In electrolytic, it's the electrode.
Anode
oxidation
both
negative
positive
Cathode: Site of reduction in both cells. In galvanic, it's the positive electrode. In electrolytic, it's the negative electrode.
Electron Flow: Always from anode to cathode via the external circuit.
Salt Bridge: Essential for galvanic cells to maintain charge neutrality; generally absent in simple electrolytic cells.
Must-Know Formula / Reaction
Spontaneity Criterion: For Galvanic Cells, ΔG < 0 (spontaneous reaction). For Electrolytic Cells, ΔG > 0 (non-spontaneous reaction, requires energy input).
Common Mistakes
Students often confuse the polarity of anode and cathode between galvanic and electrolytic cells. Remember: Oxidation at Anode, Reduction at Cathode is constant, but polarity changes.
Don't confuse the direction of energy conversion: Chemical → Electrical (Galvanic) vs. Electrical → Chemical (Electrolytic).
Forgetting the role of the salt bridge in maintaining electrical neutrality in galvanic cells.
Oxidation always at Anode, Reduction always at Cathode.
Frequently Asked Questions
What is the main difference in energy conversion between galvanic and electrolytic cells?▾
Galvanic cells convert chemical energy released from a spontaneous redox reaction into electrical energy. Electrolytic cells, conversely, use external electrical energy to drive a non-spontaneous chemical reaction, converting electrical energy into chemical energy.
How do the anode and cathode polarities differ in these two cell types?▾
In a galvanic cell, the anode is negative (site of oxidation) and the cathode is positive (site of reduction). In an electrolytic cell, the anode is positive (site of oxidation) and the cathode is negative (site of reduction), due to the external power source.
Is a salt bridge always required in electrochemical cells?▾
A salt bridge is typically essential for galvanic cells to maintain electrical neutrality in the half-cells and complete the circuit, preventing charge build-up. It is generally not required for simple electrolytic cells where both electrodes are often immersed in the same electrolyte.
Practice NEET Chemistry with AI
Get AI-powered doubt solving, personalized revision plans, and unlimited MCQ practice tailored to your weak areas.