Galvanic Cell - Voltaic Cell, Definition, Principle, Diagram with FAQs

Edited By Team Careers360 | Updated on Jul 02, 2025 05:03 PM IST

What is a galvanic cell?

A cell is an electrochemical cell that converts the energy of spontaneous redox reactions into power. Galvanic cell can be a mode of electrochemical cell where oxidation takes place. A cell is an electrochemical cell that generates electricity through chemical processes. Let's have a look at how a voltaic or cell is made.

Electrochemical cell diagram

How Galvanic Corrosion Can Be Used for Good

Electrons are transferred from one species to a special one in oxidation-reduction processes. If a reaction occurs spontaneously, energy is released. As a result, the liberated energy is put to good use. The reaction must be split into two half-reactions to deal with this energy: oxidation and reduction. The primary cell reactions are put into two distinct containers with wire so on maneuver the electrons from one end to the other.

These land up within the formation of an electrical device. Galvanic cells have typically been employed as DC power sources. An easy electric cell may contain simply one electrolyte separated by a semipermeable membrane, or it's visiting have two half-cells in an exceedingly very more complicated variant.

The salt bridge is created of an inert electrolyte, like potassium sulphate, whose ions flow into the individual half-cells to balance the fees that are built up at the electrodes. The mnemonic "Red Cat an Ox'' states that oxidation takes place at the anode and reduction takes place at the cathode. The anode is the negative terminal for the first cell current because the reaction at the anode is the source of electrons for this.

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Principle of Galvanic (Voltaic) Cell

The Gibbs energy of spontaneous redox reaction within the first cell is usually in command of the craft done by an electric cell. In most situations, it consists of two half cells and a salt bridge. Each half cell also includes a metallic electrode submerged in an electrolyte. These two half cells are externally connected to a voltmeter and a switch in metallic wires. When both electrodes are submerged within the identical electrolyte, a salt bridge isn't usually required.

Diagram of cell (voltaic cell)

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working of galvanic (voltaic) cell:

The working of an electric cell is relatively uncomplicated. It includes an action that produces power as a by-product. A cell uses the energy transfer between electrons to convert energy into electric energy during a redox reaction. The ability to separate the flow of electrons within the method of oxidation and reduction, generating a half reaction, and linking each with a wire so a conduit for the flow of electrons through such wire is produced, is used during a cell.

A current is defined because of the flow of electrons. A current of this type is created to flow via a wire so on complete a circuit and procure an output in any device, sort of television or a watch. A primary cell could also be made of any two metals. If these two metals inherit contact with each other, they'll create the anode and cathode. This mix permits more anoxic metals to experience galvanic corrosion.

In a cell, when an electrode is exposed to the electrolyte at the electrode-electrolyte interface, the metal electrode's atoms tend to supply ions within the electrolyte solution, leaving the electrons at the electrode behind. The metal electrode becomes charged as a result. On the other hand, metal ions within the electrolyte solution have a bent to decide on a metal electrode. The electrode becomes charged as a result.

Charge separation is observed under equilibrium conditions, and also the electrode is often positively or charged counting on the inclinations of two opposing reactions.

Galvanic Cell parts Anode - This electrode is where oxidation takes place. The reduction takes place at the cathode electrode. Salt bridge - A salt bridge contains the electrolytes needed to complete the circuit in a very cell.

Reduction and oxidation reactions are segregated into compartments in half-cells. External circuit - Allows electrons to travel freely between electrodes. A load might be a component during a circuit that relies on the flow of electrons to accomplish its function.

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Constructing a cell

To make a galvanic cell, you will have to follow the steps below.

Two electrodes would be great for the cell. The cathode, a charged electrode, are one altogether these electrodes, while the anode, a charged electrode, are visiting the other. The galvanic cell's two fundamental components are these two electrodes. The cathode should perform the reduction half-reaction, whereas the anode should perform the oxidation half-reaction.

Any two metals are going to be utilized to induce the reaction, as previously stated. Cell Example More than a century ago, electrochemical or galvanic cells were introduced as how for researching the thermodynamic features of fused salts. A galvanic cell, like Daniel's cell, turns energy into power.

In Daniel's cell, copper ions are reduced at the cathode, while zinc is oxidized at the anode. Galvanic cell reaction/ Daniel cell reactions at the cathode and anode are as follows:

Cathode: Cu ²⁺ + 2^e–

Anode: Zn²⁺ + 2^e–

The following are a variety of the key phrases that are utilized in galvanic cells: The two metals that operate because the cathode and anode are named as phase boundaries. The connecting bridge or medium that permits a redox reaction to need place is known as a salt bridge. The chemical processes that allow an electrical current to come back up with and flow through a cell are oxidation and reduction.

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NCERT Chemistry Notes:

Frequently Asked Questions (FAQs)

1. What's an electrochemical cell and what it's function?

An electrochemical cell could be a cell. It's wont to provide electrical current by transferring electrons via a redox process. A primary cell is an example of the way to collect energy by using simple reactions between some elements.

2. Set up of a voltaic cell?

The basic cell, also known as a voltaic cell, is made up of two electrodes, one copper and the other zinc, dipped in a dilute sulfuric acid solution in a glass jar. When the two electrodes are connected externally using a piece of wire, current flows from copper to zinc outside the cell and from zinc to copper inside the cell.

3. In a galvanic cell, why is cathode positive?

The anode is the electrode that undergoes oxidation (the loss of electrons); it is the negative electrode in a galvanic cell because electrons remain on the electrode after oxidation. As a result of the reduced positive ions of metal atoms, the cathode is a neutral electrode.

4. Daniel’s cell is a galvanic cell, right?

A galvanic cell is also known as a voltaic cell or a Daniell cell. The standard household battery is a galvanic cell example. The passage of electrons from one chemical reaction to the next occurs via an external circuit, resulting in current.

5. What is the best way to represent a galvanic cell?

Zinc and copper plates are immersed in a diluted sulfuric acid solution to make a basic voltaic cell. A voltaic cell is an electrochemical cell that generates electrical energy through a chemical reaction.

6. Why does an electrochemical cell close up after a while? Why?

After a specific amount of your time, electrochemical cells quit operating because, when one among the compounds within the electrochemical cell's anode is oxidized, the electrons are not there to reduce the molecule on the cathode side. The process ceases, and therefore the cell stops operating when the fabric at the anode doesn't have any electrons to lose.

7. What is the purpose of the salt bridge in a galvanic cell?

The salt bridge serves three crucial functions: 1) It completes the electrical circuit by allowing ions to flow between the half-cells, 2) It maintains electrical neutrality in both half-cells by providing ions to balance charge, and 3) It prevents direct mixing of the electrolyte solutions, which would cause unwanted reactions.

8. Can you explain the principle behind the operation of a galvanic cell?

The principle of a galvanic cell is based on the spontaneous transfer of electrons from a more reactive metal (anode) to a less reactive metal (cathode). This electron transfer occurs through an external circuit, generating an electric current. The difference in the tendency of the metals to lose electrons (their standard reduction potentials) determines the direction of electron flow and the voltage produced.

9. Why does the anode in a galvanic cell undergo oxidation?

The anode undergoes oxidation because it is the more reactive metal and has a greater tendency to lose electrons. In the electrochemical series, the anode has a more negative standard reduction potential, making it more likely to be oxidized (lose electrons) compared to the cathode.

10. How does a galvanic cell differ from an electrolytic cell?

The main difference is that a galvanic cell produces electricity spontaneously from a chemical reaction, while an electrolytic cell requires an external power source to drive a non-spontaneous chemical reaction. In a galvanic cell, the anode is negative and the cathode is positive, whereas in an electrolytic cell, the anode is positive and the cathode is negative.

11. How is the cathode different from the anode in a galvanic cell?

The cathode is the electrode where reduction occurs, while the anode is where oxidation takes place. The cathode gains electrons and is the positive terminal of the cell, whereas the anode loses electrons and is the negative terminal. The cathode is typically made of a less reactive metal compared to the anode.

12. What is a galvanic cell?

A galvanic cell, also known as a voltaic cell, is an electrochemical cell that converts chemical energy into electrical energy through spontaneous redox reactions. It consists of two half-cells connected by a salt bridge or porous barrier, with each half-cell containing an electrode and an electrolyte solution.

13. What is the difference between a primary and secondary galvanic cell?

A primary galvanic cell, like a typical alkaline battery, is designed for single-use and cannot be recharged effectively. The electrochemical reactions are not easily reversible. A secondary galvanic cell, such as a lead-acid battery, can be recharged by applying an external voltage to reverse the chemical reactions, allowing for multiple uses.

14. What is meant by the term "cell notation" in the context of galvanic cells?

Cell notation is a shorthand method for describing the components and arrangement of a galvanic cell. It typically follows the format: Anode | Anode solution || Cathode solution | Cathode. The double vertical line represents the salt bridge or porous barrier. For example, Zn | Zn2+ || Cu2+ | Cu describes a zinc-copper galvanic cell.

15. Can you describe the electron flow in a galvanic cell?

In a galvanic cell, electrons flow from the anode (negative terminal) through the external circuit to the cathode (positive terminal). This flow constitutes an electric current. Within the cell, ions in the electrolyte solutions complete the circuit by moving through the salt bridge or porous barrier.

16. How does a galvanic cell produce usable electricity?

A galvanic cell produces usable electricity by harnessing the energy released during spontaneous redox reactions. The cell converts chemical energy into electrical energy as electrons flow from the anode to the cathode through an external circuit. This flow of electrons can be used to power electrical devices or perform work.

17. How does temperature affect the performance of a galvanic cell?

Temperature affects galvanic cells in several ways: 1) It influences the rate of chemical reactions, generally increasing reaction rates at higher temperatures, 2) It affects the solubility of electrolytes, which can change ion concentrations, and 3) It directly impacts the cell potential as described by the Nernst equation, typically causing a slight decrease in voltage with increasing temperature.

18. How does the internal resistance of a galvanic cell affect its performance?

Internal resistance in a galvanic cell reduces its efficiency and maximum power output. It causes a voltage drop when current flows, lowering the actual voltage available at the terminals. Factors contributing to internal resistance include electrolyte concentration, electrode surface area, and the distance between electrodes.

19. How does the concept of standard hydrogen electrode (SHE) relate to galvanic cells?

The standard hydrogen electrode (SHE) serves as a reference point for measuring standard reduction potentials of other half-cells. It is assigned an arbitrary potential of 0.00 V. By comparing the potential of a half-cell to the SHE, we can determine its standard reduction potential, which is crucial for calculating cell potentials in galvanic cells.

20. How does the size of the electrodes affect the performance of a galvanic cell?

The size of the electrodes affects the surface area available for reactions. Larger electrodes generally provide more reaction sites, potentially increasing the current output of the cell. However, the cell voltage is determined by the nature of the electrodes and electrolytes, not their size. Electrode size mainly influences the cell's capacity and maximum current output.

21. How does the concept of activity relate to the concentration of electrolytes in galvanic cells?

Activity is a measure of the "effective concentration" of a species in a solution. In galvanic cells, especially at higher concentrations, the actual behavior of electrolytes may deviate from ideal behavior. The activity coefficient accounts for these deviations, providing a more accurate representation of the electrolyte's influence on cell potential than concentration alone.

22. What is meant by the term "overpotential" in the context of galvanic cells?

Overpotential refers to the additional potential (beyond the thermodynamically determined value) required to drive a half-reaction at a certain rate. It represents kinetic limitations in the electron transfer process. In galvanic cells, overpotential reduces the actual cell voltage below its theoretical value, affecting the cell's efficiency.

23. What is the significance of the Faraday constant in galvanic cell calculations?

The Faraday constant (F) represents the amount of electric charge carried by one mole of electrons. It's approximately 96,485 coulombs per mole. This constant is crucial in relating the amount of substance reacted to the quantity of electricity produced in a galvanic cell, as described by Faraday's laws of electrolysis.

24. How does the concept of standard state relate to galvanic cell potentials?

Standard state in electrochemistry refers to conditions where all species are at 1 M concentration (for solutions), 1 atm pressure (for gases), and typically at 25°C. Standard cell potentials are measured under these conditions. Understanding standard state is crucial for using standard reduction potentials to calculate cell voltages and for applying the Nernst equation to non-standard conditions.

25. How does the concept of electrochemical polarization affect galvanic cells?

Electrochemical polarization refers to the change in electrode potential when a current flows. In galvanic cells, it can reduce the cell voltage and efficiency. There are two main types: concentration polarization (due to concentration changes near the electrode surface) and activation polarization (due to the energy barrier for electron transfer). Understanding polarization is crucial for optimizing cell design and performance.

26. What is the significance of the Nernst equation in galvanic cell calculations?

The Nernst equation is crucial for calculating cell potentials under non-standard conditions. It relates the actual cell potential to the standard cell potential, taking into account the concentrations of reactants and products, as well as temperature. This equation allows for the prediction of cell behavior under various conditions and helps in understanding how concentration changes affect cell voltage.

27. How does the concept of electrochemical reversibility apply to galvanic cells?

Electrochemical reversibility in galvanic cells refers to the ability of the cell reactions to proceed in either direction with minimal energy loss. A perfectly reversible cell would have no overpotential and could be charged and discharged indefinitely. In practice, most cells show some degree of irreversibility due to factors like side reactions, electrode degradation, and concentration changes.

28. How does the concept of limiting current density apply to galvanic cells?

Limiting current density is the maximum current per unit electrode area that a galvanic cell can sustain. It occurs when the rate of ion transport to or from an electrode surface becomes the limiting factor in the cell's operation. Beyond this point, increasing the potential difference doesn't increase the current, and the cell's performance may degrade due to concentration polarization.

29. How does the concept of charge transfer resistance affect galvanic cell performance?

Charge transfer resistance represents the kinetic hindrance to the transfer of electrons between an electrode and species in the electrolyte. In galvanic cells, high charge transfer resistance can lead to decreased cell performance by causing voltage drops and reducing the maximum current output. It contributes to the overall internal resistance of the cell and is a key factor in electrode kinetics.

30. What is the significance of the Butler-Volmer equation in understanding galvanic cell kinetics?

The Butler-Volmer equation is fundamental in electrochemical kinetics. It describes the relationship between electric current and electrode potential, taking into account both the forward and reverse reactions at an electrode. In galvanic cells, this equation helps in understanding the rates of electron transfer, overpotential, and how current varies with applied potential, which is crucial for optimizing cell design and operation.

31. What is the importance of understanding concentration gradients in galvanic cells?

Concentration gradients in galvanic cells are crucial because: 1) They drive the diffusion of ions, affecting the rate of reactions, 2) They contribute to concentration polarization, which can limit cell performance, 3) They influence the cell potential as described by the Nernst equation, and 4) Understanding them is key to optimizing electrolyte composition and cell design for improved efficiency and longevity.

32. What is the significance of the exchange current density in galvanic cell kinetics?

The exchange current density is

33. What determines the voltage of a galvanic cell?

The voltage of a galvanic cell, also known as the cell potential, is determined by the difference in the standard reduction potentials of the two half-cells. It can be calculated using the Nernst equation, which takes into account the concentrations of the electrolyte solutions and the temperature of the cell.

34. How does concentration affect the voltage of a galvanic cell?

The concentration of electrolyte solutions affects the cell voltage according to the Nernst equation. Generally, increasing the concentration of reactants or decreasing the concentration of products will increase the cell voltage. This is because concentration changes alter the chemical potential of the species involved in the redox reactions.

35. What is meant by the term "standard cell potential"?

The standard cell potential (E°cell) is the potential difference between the cathode and anode of a galvanic cell under standard conditions (1 M concentration for all solutions, 1 atm pressure for gases, and typically at 25°C). It is calculated by subtracting the standard reduction potential of the anode from that of the cathode.

36. What is the significance of the electrochemical series in galvanic cells?

The electrochemical series, also known as the standard reduction potential table, is crucial for predicting the behavior of galvanic cells. It lists the standard reduction potentials of various half-reactions, allowing us to determine which species will act as the anode or cathode in a cell and to calculate the expected cell voltage.

37. What happens to the mass of the electrodes in a galvanic cell over time?

Over time, the anode loses mass as it undergoes oxidation and its atoms enter the solution as ions. Conversely, the cathode gains mass as ions from the solution are reduced and deposited on its surface. This process continues until one of the electrodes is completely consumed or the concentrations of the electrolytes reach equilibrium.

38. Can you explain the concept of electrochemical equilibrium in a galvanic cell?

Electrochemical equilibrium in a galvanic cell occurs when the cell voltage drops to zero and no net reaction takes place. This happens when the concentrations of reactants and products reach values that make the forward and reverse reactions occur at the same rate. At this point, the cell can no longer produce a current.

39. What is the role of a voltmeter in measuring the potential of a galvanic cell?

A voltmeter is used to measure the potential difference (voltage) between the anode and cathode of a galvanic cell. It is connected in parallel to the cell, with its positive terminal connected to the cell's cathode and its negative terminal to the anode. The voltmeter should have a high internal resistance to minimize current draw and ensure accurate readings.

40. What is the importance of the Gibbs free energy in understanding galvanic cells?

Gibbs free energy (ΔG) is crucial in understanding the spontaneity and energy output of galvanic cells. A negative ΔG indicates a spontaneous reaction, which is necessary for a galvanic cell to produce electricity. The relationship between ΔG and cell potential (E) is given by the equation ΔG = -nFE, where n is the number of electrons transferred and F is Faraday's constant.

41. How does the concept of electrochemical potential relate to galvanic cells?

Electrochemical potential combines both the chemical potential and the electrical potential of a species in an electrochemical system. In galvanic cells, the difference in electrochemical potential between the two half-cells drives the flow of electrons. This concept helps explain why ions move through the salt bridge and why electrons flow through the external circuit.

42. How does the concept of half-cell reactions contribute to understanding galvanic cells?

Half-cell reactions describe the separate oxidation and reduction processes occurring at the anode and cathode. Understanding these reactions is crucial because: 1) They show which species are being oxidized or reduced, 2) They help in calculating the standard cell potential when combined, and 3) They illustrate the flow of electrons and ions in the cell.

43. What is the importance of the salt bridge's ionic composition in a galvanic cell?

The ionic composition of the salt bridge is important because: 1) It must be inert and not react with the electrolytes in either half-cell, 2) It should have good ionic conductivity to maintain the flow of ions, and 3) It should provide ions that can effectively balance the charge in both half-cells without interfering with the main cell reactions.

44. What is the relationship between current and voltage in a galvanic cell?

The relationship between current and voltage in a galvanic cell is described by Ohm's law: V = IR, where V is the voltage, I is the current, and R is the resistance. As current is drawn from the cell, the voltage typically decreases due to internal resistance and polarization effects. This relationship is often represented by a polarization curve or a current-voltage characteristic curve.

45. What is the role of a separator in some types of galvanic cells?

A separator in a galvanic cell serves to physically separate the anode and cathode while allowing ion transport between them. It prevents direct contact between the electrodes, which could cause short-circuiting, while still permitting the flow of ions to complete the circuit. Separators are particularly important in compact cell designs where a traditional salt bridge is impractical.

46. What is the importance of understanding redox potentials in galvanic cells?

Understanding redox potentials is crucial because: 1) They determine which species will act as the anode or cathode, 2) They allow prediction of the direction of electron flow, 3) They are used to calculate the cell potential, and 4) They help in designing cells with desired voltage outputs by selecting appropriate electrode materials and electrolytes.

47. How does the concept of electrochemical impedance spectroscopy (EIS) relate to galvanic cell analysis?

Electrochemical impedance spectroscopy (EIS) is a powerful technique for analyzing galvanic cells. It involves applying a small alternating potential and measuring the resulting current response over a range of frequencies. EIS can provide detailed information about various cell processes, including charge transfer kinetics, diffusion limitations, and the behavior of the electrode-electrolyte interface, helping in cell characterization and optimization.

48. How does the concept of electrochemical potential energy relate to the work done by a galvanic cell?

The electrochemical potential energy in a galvanic cell represents the maximum electrical work the cell can perform. It's directly related to the cell potential and the amount of charge transferred. The work done by the cell (W) is given by W = -nFE, where n is the number of moles of electrons transferred, F is Faraday's constant, and E is the cell potential. This relationship links the chemical energy stored in the cell to the electrical energy it can produce.