Question

75\. An electrochemical cell that produces a current from an oxidation- reduction reaction is often called a(n) ____ cell.

Short answer

An electrochemical cell that produces a current from an oxidation-reduction reaction is often called a \(Voltaic\) or \(Galvanic\) cell.

Step-by-step solution

Understand the Concepts

An electrochemical cell is a system that can either generate electrical energy from chemical reactions or use electrical energy to cause chemical reactions. The reactions in an electrochemical cell involve processes known as oxidation and reduction which are collectively referred to as redox reactions. Oxidation is the loss of electrons and reduction is the gain of electrons. The cell that generates an electric current or flow of electrons, as a result of these redox reactions, is specifically called a Voltaic or Galvanic cell.

Application of Knowledge

With the understanding that an electrochemical cell which produces a current from an oxidation-reduction, or redox, reaction is a Voltaic or Galvanic cell, we can accurately fill in the blank. So, the completed sentence reads: "An electrochemical cell that produces a current from an oxidation-reduction reaction is often called a Voltaic or Galvanic cell."

Key concepts

Oxidation-Reduction Reactions

Oxidation-reduction reactions, commonly known as redox reactions, are chemical processes where the transfer of electrons occurs. In these reactions, one substance loses electrons, known as oxidation, while another gains electrons, known as reduction.
Redox reactions are fundamental to many chemical processes and are essential in electrochemical cells. These reactions can be recognized by:

• The presence of a substance that loses electrons, called the reducing agent.
• A substance that gains electrons, known as the oxidizing agent.

In electrochemical cells, redox reactions occur at two electrodes. At the anode, oxidation takes place, whereas at the cathode, reduction happens. The flow of electrons from the anode to the cathode through an external circuit generates an electric current.
Understanding these reactions is crucial, as they are the driving force behind the functioning of Voltaic and Galvanic cells.

Voltaic Cells

Voltaic cells, also known as galvanic cells, are a type of electrochemical cell that converts chemical energy into electrical energy through spontaneous redox reactions. These cells are named after Alessandro Volta, a pioneer of electricity.
A voltaic cell consists of two half-cells, each containing an electrode and an electrolyte. The electrodes are typically made of different metals, immersed in their respective ionic solutions.
Here’s a simplified view of how a voltaic cell operates:

• The anode is the electrode where oxidation occurs, and electrons are released.
• The cathode is where reduction occurs, accepting the electrons released from the anode.
• The movement of electrons from the anode to the cathode through an external wire creates an electric current.
• A salt bridge or porous barrier is often used, allowing ions to flow between the two half-cells and maintain electrical neutrality.

Voltaic cells are the basis of batteries, powering a wide range of devices from flashlights to laptops.

Galvanic Cells

Galvanic cells are identical in functionality to voltaic cells; the terms are often used interchangeably. Both refer to electrochemical cells capable of converting chemical energy from spontaneous redox reactions into electrical energy. The name “galvanic” honors Luigi Galvani, another significant figure in the study of electricity.
These cells are characterized by their ability to produce electrical energy without additional input, unlike electrolytic cells, which require electrical energy to drive chemical reactions.
Key components of a galvanic cell include:

• An anode, where the oxidation reaction releases electrons.
• A cathode, where the reduction reaction absorbs electrons.
• An external circuit for electron flow, connecting the anode to the cathode.
• A salt bridge, crucial for the movement of ions between the two half-cells, preventing charge imbalance.

The efficient design of galvanic cells has paved the way for many technological advancements, offering a portable and reliable source of power for various applications.