The question seems to contain a typo, as it asks for the difference between "electrolytic cell and electrolytic cell." Based on the context and references provided, it is likely that the intended comparison is between an electrolytic cell and a galvanic cell (also known as a voltaic cell). Both are types of electrochemical cells, but they serve opposite purposes. Electrolytic cells use external electrical energy to drive non-spontaneous chemical reactions, while galvanic cells generate electrical energy from spontaneous chemical reactions. Below is a detailed explanation of the differences between these two types of cells.
Key Points Explained:
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Purpose and Energy Conversion:
- Electrolytic Cell: Converts electrical energy into chemical energy. It requires an external power source to drive a non-spontaneous chemical reaction. Examples include electroplating and recharging batteries.
- Galvanic Cell: Converts chemical energy into electrical energy. It generates electricity through a spontaneous chemical reaction. Examples include batteries and fuel cells.
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Reaction Spontaneity:
- Electrolytic Cell: Involves non-spontaneous reactions, meaning the reaction does not occur naturally without an external energy input. The Gibbs free energy change (ΔG) is positive.
- Galvanic Cell: Involves spontaneous reactions, meaning the reaction occurs naturally and releases energy. The Gibbs free energy change (ΔG) is negative.
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Electrode Charges:
- Electrolytic Cell: The anode is positively charged, and the cathode is negatively charged. Oxidation occurs at the anode, and reduction occurs at the cathode.
- Galvanic Cell: The anode is negatively charged, and the cathode is positively charged. Oxidation occurs at the anode, and reduction occurs at the cathode.
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Energy Source:
- Electrolytic Cell: Requires an external power source (e.g., a battery or power supply) to force electrons to flow and drive the reaction.
- Galvanic Cell: Does not require an external power source; it generates its own electrical energy from the chemical reaction.
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Applications:
- Electrolytic Cell: Used in processes like electrolysis (e.g., splitting water into hydrogen and oxygen), electroplating (e.g., coating metals with a thin layer of another metal), and recharging rechargeable batteries.
- Galvanic Cell: Used in batteries (e.g., AA batteries, lithium-ion batteries) and fuel cells to provide portable electrical energy.
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Electron Flow:
- Electrolytic Cell: Electrons are forced to flow from the external power source to the cathode, driving the reduction reaction.
- Galvanic Cell: Electrons flow spontaneously from the anode to the cathode through an external circuit, generating electrical current.
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Equilibrium and Current Flow:
- Electrolytic Cell: Operates under non-equilibrium conditions, with an external voltage driving the reaction.
- Galvanic Cell: Operates under equilibrium conditions when no current flows, but generates current when connected to an external circuit.
By understanding these key differences, one can better appreciate the distinct roles and applications of electrolytic and galvanic cells in various scientific and industrial contexts.
Summary Table:
| Aspect | Electrolytic Cell | Galvanic Cell |
|---|---|---|
| Purpose | Converts electrical energy into chemical energy | Converts chemical energy into electrical energy |
| Reaction Spontaneity | Non-spontaneous (requires external energy) | Spontaneous (occurs naturally) |
| Electrode Charges | Anode: Positive, Cathode: Negative | Anode: Negative, Cathode: Positive |
| Energy Source | Requires external power source | Generates its own electrical energy |
| Applications | Electroplating, recharging batteries | Batteries, fuel cells |
| Electron Flow | Forced flow from external source to cathode | Spontaneous flow from anode to cathode |
| Equilibrium | Operates under non-equilibrium conditions | Operates under equilibrium conditions |
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