What is the Difference Between Voltaic Cell and Electrolytic Cell

The main difference between voltaic cell and electrolytic cell is that a voltaic cell is designed to convert chemical energy into electrical energy, whereas an electrolytic cell is designed to use electrical energy to drive a non-spontaneous redox reaction.

Voltaic cells and electrolytic cells are two fundamental types of electrochemical cells. These cells play important roles in various industrial, scientific, and practical applications, demonstrating the dynamic interplay between chemistry and electrical energy.

Key Areas Covered

1. What are Voltaic Cells
      – Definition, Features, Applications
2. What are Electrolytic Cells
      – Definition, Features, Applications
3. Similarities Between Voltaic Cell and Electrolytic Cell
      – Outline of Common Features
4. Difference Between Voltaic Cell and Electrolytic Cell
      – Comparison of Key Differences
5. FAQ: Voltaic Cell and Electrolytic Cell
      – Frequently Asked Questions

Key Terms

Voltaic Cell, Electrolytic Cell

What are Voltaic Cells

Voltaic cells are electrochemical devices that convert chemical energy directly into electrical energy through a spontaneous redox (reduction-oxidation) reaction. The fundamental principle behind their operation is the separation of the redox reaction into two half-reactions, each occurring at one of two electrodes: the anode and the cathode. At the anode, oxidation takes place. In this process, electrons are liberated from the reactant, and the reactant species is oxidized. This loss of electrons generates an electric current. At the cathode, reduction occurs. Electrons from the anode travel through an external circuit to the cathode, where another reactant species accepts them. This results in a reduction reaction.

The two half-reactions are coupled by an external electrical circuit, allowing electrons to flow from the anode to the cathode, creating an electrical current. The electrochemical cell is completed by an ionic bridge or an electrolyte that permits the flow of ions between the anode and the cathode, maintaining charge neutrality in the system.

One of the most famous examples of a voltaic cell is the Daniell cell, which consists of a copper anode and a zinc cathode in a solution of copper sulfate and zinc sulfate. As the zinc anode undergoes oxidation, it releases electrons, while the copper cathode accepts these electrons, facilitating the reduction of copper ions. This flow of electrons creates an electric current, which can be harnessed to power external devices.

Applications of Voltaic Cells

Voltaic cells find a wide array of applications across various domains, from everyday gadgets to large-scale industrial processes. They power portable devices like smartphones and laptops, electric vehicles, and renewable energy systems, contributing to sustainable energy solutions. In the field of medicine, miniature voltaic cells support implantable devices, while in environmental monitoring, they enable remote sensors to function in off-grid locations. Voltaic cells play a critical role in space exploration by capturing and converting solar energy for spacecraft and satellites. Additionally, they offer emergency backup power through uninterruptible power supplies (UPS) and facilitate chemical synthesis in laboratories and industrial processes by driving non-spontaneous chemical reactions.

What are Electrolytic Cells

Electrolytic cells are a type of electrochemical cell that operates in a process called electrolysis. Unlike galvanic cells or voltaic cells, which spontaneously generate electrical energy from chemical reactions, electrolytic cells use electrical energy to drive non-spontaneous chemical reactions.

In an electrolytic cell, an external source of electrical power is connected to the cell, and this electrical energy is used to cause a chemical change. Specifically, it forces a non-spontaneous redox reaction to occur in the cell, where substances are either reduced or oxidized.

Electrolytic cells have a diverse range of applications in various industries. They are used for electroplating, enhancing the appearance and durability of products, water electrolysis to produce hydrogen and oxygen gases, chlorine production from brine, and aluminum extraction from bauxite. Additionally, electrolytic cells play a key role in electrowinning and electrorefining processes to extract and purify metals, as well as in the production of electrolytic capacitors for electronic devices. They facilitate chemical synthesis, both in laboratory and industrial settings, by providing the electrical energy needed for specific reactions. Moreover, electrolytic cells can be employed in environmental remediation efforts, such as wastewater treatment and heavy metal removal from industrial effluents, making them essential tools in a wide array of applications.

Similarities Between Voltaic Cell and Electrolytic Cell

• In both types of cells, redox (reduction-oxidation) reactions are essential.
• Both voltaic cells and electrolytic cells consist of two electrodes: the anode and the cathode.

Difference Between Voltaic Cell and Electrolytic Cell

Definition

Voltaic cells are cells designed to convert chemical energy into electrical energy, while electrolytic cells are cells designed to use electrical energy to drive non-spontaneous redox reactions.

Generation of Electrical Energy

Voltaic cells spontaneously generate electrical energy from chemical reactions. They convert chemical energy into electrical energy. However, electrolytic cells use electrical energy from an external source to drive non-spontaneous chemical reactions. Moreover, they require an input of electrical energy to operate and facilitate chemical changes.

Redox Reactions

The redox reactions in voltaic cells are spontaneous, meaning they occur without any external electrical influence, while the redox reactions in electrolytic cells are non-spontaneous and require an external electrical energy source to make them occur.

Anode and Cathode

In a voltaic cell, the anode is the negative terminal (electron source), and the cathode is the positive terminal (electron sink). However, in an electrolytic cell, the positive terminal of the external power source is connected to the anode, and the negative terminal is connected to the cathode.

FAQ: Voltaic Cell and Electrolytic Cell

Is the battery a voltaic cell?

No. A battery is not a voltaic cell. It is an electrolytic cell.

Which feature is the same in a voltaic cell and an electrolytic cell?

The feature that is the same in both a voltaic cell and an electrolytic cell is the presence of two electrodes: an anode and a cathode. These electrodes are where the redox (reduction-oxidation) reactions occur in both types of cells.

What is the difference between electrolytic and voltaic reaction?

The key difference between electrolytic and voltaic reactions is that voltaic reactions are spontaneous and generate electrical energy from chemical reactions, while electrolytic reactions are non-spontaneous and require an input of electrical energy to drive chemical changes.

Conclusion

The main difference between voltaic cell and electrolytic cell is that voltaic cell is designed to convert chemical energy into electrical energy, whereas an electrolytic cell is designed to use electrical energy to drive a non-spontaneous redox reaction.

Reference:

1. “Galvanic Cell.” Byju’s.
2. “Electrolytic Cell.” Byju’s.

Image Courtesy:

1. “Voltaic cell diagram” By Puchatech K. (CC BY-SA 3.0) via Commons Wikimedia
2. “Electrolytic cell charge” By RodEz2 – Own work (CC BY-SA 3.0) via Commons Wikimedia