Electrolytic vs Electrochemical Cell: Definitions, Working, and Comparison Table
Understanding the Difference Between Electrolytic and Electrochemical Cell is crucial for mastering electrochemistry in JEE Main. Both cells are foundational in redox reaction concepts but differ sharply in construction, working, and energy conversion. This article gives a clear, exam-ready comparison, using real examples and match-pointed lists to help you revise faster and remember longer.
Electrochemical cells generate electrical energy from spontaneous reactions, whereas electrolytic cells use electricity to drive non-spontaneous chemical changes. Each plays a unique role in batteries, industrial electrolysis, plating, and more. Grasping these distinctions ensures problem-solving accuracy in JEE Main and clarifies where and why each cell is used in real-world chemistry.
What is an Electrolytic Cell?
An electrolytic cell is a device that converts electrical energy into chemical energy by forcing a non-spontaneous reaction to occur. It consists of two electrodes—anode (positive) and cathode (negative)—immersed in an electrolyte. An external power source like a battery applies voltage, causing cations to migrate to the cathode (reduced) and anions to the anode (oxidized). This setup is common in electrolysis processes, such as water splitting (2H2O → 2H2 + O2) and electroplating metals.
Key features of an electrolytic cell:
- Requires an external power source to operate.
- The anode is positive, cathode is negative.
- Cations migrate to the cathode; anions to the anode.
- Drives non-spontaneous redox reactions.
- Applications: electrolysis of NaCl, refining aluminium, electroplating.
What is an Electrochemical Cell?
An electrochemical cell (or galvanic cell) is a device that converts chemical energy into electrical energy through a spontaneous redox reaction. It has two electrodes—anode (negative, oxidation) and cathode (positive, reduction)—in separate half-cells connected by a salt bridge. When the two half-cells are joined, electrons flow from the anode to the cathode via an external circuit, generating current, like in a battery.
Key features of electrochemical cells:
- No external power source required—reaction is spontaneous.
- The anode is negative, cathode is positive.
- Oxidation at anode, reduction at cathode.
- Electron flow externally from anode to cathode.
- Common examples: Daniell cell, dry cell, lead-acid battery.
Difference Between Electrolytic and Electrochemical Cell (Tabular Form)
| Aspect | Electrolytic Cell | Electrochemical Cell |
|---|---|---|
| Energy Conversion | Electrical to chemical (non-spontaneous reaction) | Chemical to electrical (spontaneous reaction) |
| External Power Source | Required | Not required |
| Anode/Cathode Polarity | Anode: positive, Cathode: negative | Anode: negative, Cathode: positive |
| Redox Reaction | Non-spontaneous, driven by applied EMF | Spontaneous redox reaction |
| Electron Flow | From anode to cathode within cell | From anode to cathode through external circuit |
| Applications | Electrolysis, metal extraction, electroplating | Batteries, fuel cells |
You can remember: Electrolytic cells need electrical input; electrochemical (galvanic) cells provide an electrical output.
How to Identify: Electrolytic vs Electrochemical Cell
In JEE numericals, follow these tips to identify the cell type:
- If an external voltage source is present, it's electrolytic.
- Anode positive? Likely electrolytic; anode negative? Electrochemical.
- Reaction is non-spontaneous (ΔG > 0): Electrolytic.
- Cell produces current with no applied voltage: Electrochemical.
- Watch keywords: "Electrolysis", "electroplating" → electrolytic; "battery", "galvanic" → electrochemical.
Working Principles with Diagram Cues
A well-labelled diagram helps visualize each setup. In an electrochemical cell, the salt bridge completes the circuit between half-cells, with electrons flowing from the zinc anode (oxidation) to the copper cathode (reduction) in the external wire. In an electrolytic cell, a battery’s positive terminal is connected to the anode, causing oppositely charged ions to migrate to their respective electrodes and enabling processes like water splitting or purification of copper.
Key Examples & Applications
Electrochemical and electrolytic cells appear often in real-life and industry. For JEE Main, focus on these:
- Dry cells and batteries – Electrochemical cells found in electronic gadgets.
- Electrolysis of molten NaCl – Electrolytic, yielding Na(s) and Cl2(g).
- Aluminium extraction by Hall-Héroult process – Electrolytic.
- Galvanic (Daniell) cell – Textbook electrochemical cell using Zn and Cu electrodes.
- Electroplating of metals – Practical use of electrolytic cells for coating objects.
Understanding the role of redox reactions, cell potential, and application context helps in tackling JEE Main MCQs and assertion-reason problems.
Summary: Electrolytic vs Electrochemical Cell
Electrolytic cells transform electrical into chemical energy, drive non-spontaneous reactions with an external power source, and have a positive anode. Electrochemical cells (galvanic) do the opposite, generating electricity from chemical energy via spontaneous redox reactions, with a negative anode. Recognizing their differences is essential for scoring full marks on questions about energy conversion, cell polarity, and industrial applications.
More JEE Main Chemistry Resources
- Redox Reactions and Electrochemistry Mock Test 1
- Redox Reactions and Electrochemistry Mock Test 2
- Redox Reactions and Electrochemistry Mock Test 3
- Equilibrium: Complete JEE Revision
- Difference Between Galvanic and Electrolytic Cell
- Biomolecules Practice Paper
- Chemical Thermodynamics: Key Formulae and Revision
- Cell vs Battery: JEE Mains
- Redox Reactions Explained for JEE
- Hall-Héroult Process for Aluminium
- Primary vs Secondary Cells
- Electrochemical Series in Electrochemistry
- Applications of Electrolysis
For more JEE Main Chemistry topics and revision materials, keep exploring Vedantu. Mastering the Difference Between Electrolytic and Electrochemical Cell builds confidence for numerical and theoretical exam sections.
FAQs on Difference Between Electrolytic and Electrochemical Cell Explained
1. What is the difference between electrolytic and electrochemical cell?
Electrolytic cells use electrical energy to drive a non-spontaneous chemical reaction, while electrochemical (galvanic) cells generate electrical energy from a spontaneous reaction.
Key differences include:
- Electrolytic Cell: Requires an external power source; non-spontaneous reaction occurs.
- Electrochemical Cell: Produces electric current as a spontaneous redox reaction occurs.
- Electrode Polarity: Anode is positive in electrolytic, negative in electrochemical.
- Application: Electroplating uses electrolytic; batteries use electrochemical.
2. How can you identify if a cell is galvanic or electrolytic?
You can identify the cell type by observing energy flow and the direction of reaction:
- Galvanic Cell: Produces electricity from a spontaneous reaction; anode is negative, cathode is positive.
- Electrolytic Cell: Consumes electricity to drive a non-spontaneous reaction; anode is positive, cathode is negative.
- Power Source: Presence of an external power supply indicates an electrolytic cell.
3. What are the applications of electrolytic and electrochemical cells?
Electrolytic and electrochemical cells have important real-life and industrial uses.
- Electrolytic Cell: Electroplating, metal extraction, water electrolysis, and purification of metals.
- Electrochemical Cell: Dry cell, Daniel cell, lead-acid battery, fuel cells.
4. Is a battery an electrolytic or an electrochemical cell?
Batteries are typically electrochemical (galvanic) cells. They convert stored chemical energy into electrical energy through spontaneous redox reactions.
- Example: Dry cell batteries, lead-acid batteries in vehicles.
- Some rechargeable batteries act as electrolytic cells during charging and electrochemical cells during discharge.
5. Do the electrodes have the same polarity in both electrolytic and electrochemical cells?
No, the polarity of electrodes differs between cell types.
- Electrolytic Cell: Anode is positive, cathode is negative.
- Electrochemical (Galvanic) Cell: Anode is negative, cathode is positive.
6. Can you give examples of electrolytic and electrochemical cells?
Common examples help distinguish between the two cell types:
- Electrolytic Cell: Electrolytic refining of copper, water electrolysis, electroplating setup.
- Electrochemical Cell: Daniel cell, dry cell, lead-acid accumulator, fuel cell.
7. How does electrolysis differ from reactions in an electrochemical cell?
Electrolysis (in electrolytic cells) requires external voltage to force a reaction, while electrochemical cells generate voltage from a spontaneous reaction.
- Electrolysis: Non-spontaneous change, e.g., splitting water into hydrogen and oxygen.
- Electrochemical Cell: Spontaneous redox change, e.g., electricity production in batteries.
8. What is the working principle of an electrolytic cell?
An electrolytic cell works by applying an external voltage to drive a non-spontaneous chemical reaction. This process is called electrolysis.
- Electrons flow from anode to cathode through wires, while ions move in solution to balance charges.
- Electricity is used to cause a chemical change, such as metal deposition or decomposition of compounds.
9. Are all batteries based on electrochemical cells?
Most batteries are based on electrochemical (galvanic) cell principles. They generate electrical energy from chemical reactions.
- Primary cells: Non-rechargeable (e.g., dry cells) use a one-way electrochemical reaction.
- Secondary cells: Rechargeable (e.g., lead-acid, lithium-ion) behave as electrochemical cells when discharging and as electrolytic cells when charging.
10. How does energy conversion differ in electrolytic and electrochemical cells?
Energy conversion direction is the main distinction between these cells.
- Electrolytic Cell: Converts electrical energy to chemical energy.
- Electrochemical Cell: Converts chemical energy to electrical energy.
