Galvanic Cell

Definition

A galvanic cell, also known as a voltaic cell, is an electrochemical cell that generates an electric current through a spontaneous redox (reduction-oxidation) reaction. It is a device that converts the chemical energy of a spontaneous redox reaction into electrical energy.

5 Must Know Facts For Your Next Test

1. In a galvanic cell, the spontaneous redox reaction occurs between two different metals or a metal and a non-metal, creating a potential difference that drives the flow of electrons.
2. The anode is the electrode where oxidation occurs, and the cathode is the electrode where reduction occurs, generating an electric current.
3. The electrolyte solution in a galvanic cell allows the flow of ions between the anode and cathode, completing the circuit and enabling the continuous flow of electrons.
4. The cell potential, or voltage, of a galvanic cell is determined by the difference in the standard reduction potentials of the two half-reactions occurring at the anode and cathode.
5. Galvanic cells have a wide range of applications, including in batteries, electroplating, and as a means of preventing corrosion.

Review Questions

• Explain the role of spontaneous redox reactions in the operation of a galvanic cell.
  • In a galvanic cell, the spontaneous redox reaction is the driving force that generates an electric current. The redox reaction occurs between two different metals or a metal and a non-metal, with one substance undergoing oxidation (losing electrons) at the anode and the other undergoing reduction (gaining electrons) at the cathode. This electron transfer creates a potential difference between the two electrodes, which allows the flow of electrons through an external circuit, producing an electric current.
• Describe how the cell potential of a galvanic cell is determined and how it relates to the standard reduction potentials of the half-reactions.
  • The cell potential, or voltage, of a galvanic cell is determined by the difference in the standard reduction potentials of the two half-reactions occurring at the anode and cathode. The reduction potential of the cathode half-reaction is always greater than the reduction potential of the anode half-reaction. This difference in reduction potentials creates the potential difference that drives the flow of electrons through the external circuit, generating an electric current. The cell potential can be calculated using the formula: $\text{Cell Potential} = \text{Cathode Reduction Potential} - \text{Anode Reduction Potential}$.
• Analyze the role of the electrolyte solution in a galvanic cell and explain how it contributes to the continuous flow of electrons.
  • The electrolyte solution in a galvanic cell plays a crucial role in enabling the continuous flow of electrons. The electrolyte allows the movement of ions between the anode and cathode, completing the circuit and allowing the redox reaction to occur. As the oxidation reaction takes place at the anode, the released electrons flow through the external circuit to the cathode, where the reduction reaction occurs. The ions in the electrolyte solution migrate to maintain electrical neutrality and balance the charge, ensuring the continuous flow of electrons and the generation of an electric current. Without the electrolyte, the circuit would be incomplete, and the galvanic cell would not be able to function.

Related terms

Reduction:

The process of gaining electrons, which decreases the oxidation state of an element.

Oxidation:

The process of losing electrons, which increases the oxidation state of an element.

Spontaneous Reaction: A reaction that occurs naturally without the input of external energy, driven by a decrease in the Gibbs free energy of the system.