Have you ever wondered how a battery works or why one end is marked with a plus and the other with a minus? That’s where the concepts of cathode and anode come in. These two terms are super important in chemistry and physics, especially when you’re learning about electrolysis, batteries, or electroplating.

In this article, we’ll break down what cathode and anode mean, how they work, and how to easily remember the difference between them with simple examples to help you understand better.

Download NEET UG Questions on Cathode And Anode

Cathode and Anode 

An electrode is a conductor through which electric current enters or leaves an electrolyte used in an electrolytic cell. Electrodes can be divided into two types; anode and cathode. The anode is the electrode at which oxidation occurs and electrons flow out of the electrolyte, while the cathode is the electrode at which reduction occurs and electrons flow into the electrolyte. The flow of electrons between the anode and cathode creates an electric current. 

The electrode in an electrochemical cell at which reduction occurs is called the cathode. Thus, electrons are gained by the atoms or molecules at the cathode, resulting in the formation of negatively charged ions or neutral molecules. The cathode is typically the electrode that is connected to the negative terminal of a power source.

During a chemical reaction, electrons flow from the anode (the electrode at which oxidation occurs) to the cathode, creating a current. The cathode is also the electrode where the reduction half-reaction of a redox reaction occurs. This half-reaction involves the gaining of electrons, which can be represented by the addition of electrons to the reactants. 

Examples of Cathode

Some examples of cathodes in different types of electrochemical cells include:

• In a standard dry cell battery, the carbon rod acts as the cathode.
• In an electrolysis cell, the electrode at which hydrogen is produced is the cathode. 
• In a mercury vapor lamp, the mercury inside the bulb is ionized by an electric current, and the cathode is responsible for emitting the electrons that ionize the mercury. 
• In a cathode ray tube (CRT) display, the electron gun emits electrons that are focused and accelerated toward the fluorescent screen, which acts as the cathode. 

Anode

An anode is the electrode at which oxidation occurs in an electrochemical cell. It is the terminal where electrons flow out of the device and into the external circuit. This means that electrons are lost from the anodic material to the external circuit, and the anode becomes positively charged. 

The anode is the positive electrode in a galvanic cell and the negative electrode in an electrolytic cell. In a simple galvanic cell, the anode is the electrode where the oxidation of the anodic material occurs and electrons are lost. In contrast, in an electrolytic cell, the anode is the electrode where electrons are supplied to the electrolyte. 

Examples of Anode

There are many examples of anodes in different types of electrochemical cells. Here are a few examples:

• In a primary zinc-carbon dry cell battery, the zinc metal is the anode and the carbon rod is the cathode.
• In a lithium-ion battery, the anode is typically made of lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), or lithium iron phosphate (LiFePO4).
• In a lead-acid battery, the anode is made of lead. 
• In an electrorefining process, the impure metal that is dissolved in the electrolyte is the anode, it corrodes and loses electrons to the electrolyte while the pure metal is deposited on the cathode.

Difference between Anode and Cathode

The main differences between anodes and cathodes in electrochemical cells are discussed in the table below:

Common Misconceptions About Cathode and Anode

Ace your exams and level up your preparation game with Testbook's curated study materials and exam practice sets. Download the Testbook App for free today to take advantage of some exclusive offers now.