Comparison between Galvanic and Electrolytic Cell
Understanding the comparison between galvanic and electrolytic cells is essential for mastering electrochemistry in the Cambridge A-Level syllabus. Students tend to get mixed up between the two types of electrochemical cells. This table will illustrate the comparison between galvanic and electrolytic cell.
Comparison between galvanic and electrolytic cell table
Let’s break it down step by step.
Galvanic Cells
Also known as voltaic cells, galvanic cells convert chemical energy into electrical energy through spontaneous redox reactions. The most common example is the Daniell cell, where zinc and copper electrodes create an electric current.
- Electrode Polarity: In a galvanic cell, the anode (where oxidation occurs) is negative, and the cathode (where reduction occurs) is positive.
- Electron Flow: Electrons flow from the negative anode to the positive cathode through an external circuit.
- Applications: These cells power batteries and other portable devices.
Electrolytic Cells
Electrolytic cells, on the other hand, use electrical energy to drive non-spontaneous redox reactions. A classic example is electroplating, where an electric current deposits a thin layer of metal onto a surface.
- Electrode Polarity: In an electrolytic cell, the anode is positive, and the cathode is negative because the power source forces the flow of electrons.
- Electron Flow: Electrons are pushed from the power source to the negative cathode, causing reduction. The positive anode loses electrons, leading to oxidation.
- Applications: Used in electroplating, electrolysis of water, and industrial processes like aluminum extraction.
Key Differences
The main distinction lies in energy conversion: galvanic cells generate electricity, while electrolytic cells consume electricity. Additionally, the polarity of the electrodes is reversed in the two systems. A useful acronym, P.A.N.I.C. for electrolytic cell polarity (Positive is Anode Negative is Cathode). Then just remember polarity is reversed for galvanic cell.
Here’s a link to a video explanation!
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