Cathode and Anode Electrodes in Chemistry Explained with Functions and Key Differences

In electrochemistry, understanding the cathode and anode is crucial because almost every electrical or chemical cell operates on these two electrodes. This article provides insights into identifying anode and cathode in different situations, remembering their charges, understanding electron flow, and confidently answering exam questions. Before we understand what an anode is and a cathode, it's important to understand the term electrode.

Table of Content 

• What is an Electrode
• What is a Cathode and Anode
• Cathode and Anode in Electrolytic Cells and Galvanic Cells
• Difference Between Anode and Cathode

What is an Electrode

An electrode is a substance that conducts electricity and allows electric current to enter or leave a non-metallic medium, such as an electrolyte.

In simple words, an electrode helps transfer electric charge between a circuit and a solution. Electrodes are usually made of metals or graphite and are placed inside an electrolytic cell or an electrochemical cell.

Every electrical cell has two electrodes:

• Anode
• Cathode

These two electrodes are identified based on the direction of current flow and the type of chemical reaction occurring at them.

Let's have a closer into what a cathode and an anode are 

What Is a Cathode and Anode

Cathode and anode are two types of electrodes through which electric current enters or leaves a chemical system.

But what happens at the Cathode and the Anode? 

• The cathode is the electrode where reduction takes place
• Anode is the electrode where oxidation takes place

These definitions remain the same in all types of cells and are the most important rule to remember.

A cathode is the electrode at which reduction occurs, meaning it gains electrons.

When it comes to the Cathode, the following changes take place: 

• Reduction always takes place at the cathode
• Electrons move towards the cathode
• Positively charged ions (cations) are attracted to it

The fact that the Charge of the Cathode in different cells varies like: 

• Electrolytic cell: Cathode is negative
• Galvanic cell: Cathode is positive

For Example:

In a galvanic cell, copper acts as the cathode where Cu²⁺ ions gain electrons and form copper metal.

On the other hand, An anode is the electrode at which oxidation occurs, meaning it loses electrons.

When it comes to the anode, the following changes take place: 

• Oxidation always takes place at the anode
• Electrons move away from the anode
• Negatively charged ions (anions) are attracted to it

Charge of the Anode in different cells: 

• Electrolytic cell: Anode is positive
• Galvanic cell: Anode is negative

For Example:

In electrolysis, chloride ions move to the anode and lose electrons during oxidation.

Now, let's understand in more detail how the cathode and anode vary in different cells.

Cathode and Anode in Electrolytic Cells and Galvanic Cells 

An electrolytic cell uses electrical energy to cause a chemical reaction. The anode is connected to the positive terminal of the battery, and the Cathode is connected to the negative terminal. 

What is observed :

• Oxidation happens at the anode
• Reduction happens at the cathode

For Example:

During electrolysis of molten sodium chloride:

• Na⁺ ions move to the cathode and are reduced
• Cl⁻ ions move to the anode and get oxidised

On the other hand, the Cathode and Anode in a Galvanic cell produce electricity from a chemical reaction.

• The anode is negative
• The cathode is positive

What Happens is: 

• Electrons flow from the anode to the cathode
• Electrical energy is produced due to redox reactions

For Example, in a zinc–copper cell:

• Zinc acts as the anode and gets oxidised
• Copper acts as the cathode and gets reduced

Now, summarising the difference between anode and cathode to understand it in a better way.

Difference Between Anode and Cathode

Basis	Anode	Cathode
Type of reaction	Oxidation	Reduction
Electron behaviour	Loses electrons	Gains electrons
Charge in the electrolytic cell	Positive	Negative
Charge in a galvanic cell	Negative	Positive
Ion attracted	Anions	Cations
Symbol	A	K

Read More: Difference Between Compound and Mixtures 

The Anode and cathode in chemistry are essential parts of electrochemical and electrolytic cells. The anode is the site of oxidation, while the cathode is the site of reduction. Although their charges change depending on the type of cell, their functions remain the same.