Oxidation vs. Reduction: What’s the Difference?

Oxidation and reduction are two important chemical processes that occur in the body that have opposite effects on certain chemical compounds. While it may be obvious what oxidation does, there’s some confusion about what reduction means and why it’s significant. In this article, we’ll clear up the confusion surrounding these two terms and why they are so important to your health.

What is Oxidation?

The oxidation process involves losing electrons by a molecule, atom, or ion. When this happens, the structure of the molecule changes and it becomes more unstable. This can happen when oxygen reacts with another element, like iron. The resulting compound is called an oxide. Iron oxide, for example, is rust.


The opposite of oxidation is reduction. Reduction occurs when electrons are added to a molecule to stabilize it. In some cases, this addition causes the original substance to decompose into two substances with different properties.

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What is Reduction?

Reduction occurs when electrons from a reducing agent combine with molecules containing hydrogen. This causes the hydrogen molecule to gain an extra electron. The result is a stable molecule with a net positive charge.


In some cases, the reduction can produce other chemical changes, such as removing oxygen or nitrogen from a compound. In general, it is considered that an increase in the oxidation state corresponds to an increase in the energy content of the system, and conversely, a decrease in the oxidation state corresponds to the lower energy content of the system.

Difference Between Oxidation vs. Reduction

In a nutshell, oxidation is the loss of electrons and reduction is the gain of electrons. But what does that mean? Let’s take a closer look. When you do an experiment in which you heat copper metal until it turns blue-green, then copper has been oxidized. When you do an experiment in which zinc metal reacts with hydrochloric acid to form hydrogen gas bubbles and zinc chloride solution, then zinc has been reduced. Why do they happen like this? Copper loses electrons when heated, so it becomes more positive or less negative. Zinc gains electrons when reacted with HCl (hydrochloric acid), so it becomes more negative or less positive. The lesson here is that all elements have atoms with equal numbers of protons and neutrons in their nuclei, but some have more than others.

Comparing and Contrasting Redox Reactions

Redox reactions are a type of chemical reaction that involves the transfer of electrons between two molecules. In oxidation-reduction reactions, one molecule loses electrons and is oxidized, while the other molecule gains electrons and is reduced.

The key to understanding redox reactions is to identify which molecule is being oxidized and which is being reduced.In general, oxidation reactions are characterized by an increase in oxidation state, while reduction reactions are characterized by a decrease in oxidation state.

Examples of Redox Reactions

A redox reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes.

Here are some examples of redox reactions:

  • Iron (Fe) reacts with oxygen (O2) to form iron oxide (FeO).
  • Potassium permanganate (KMnO4) oxidizes lead(II) chloride to lead(IV) chloride when it reacts with chlorine gas.
  • In a catalytic converter, platinum and palladium react with hydrocarbons such as methane to form carbon dioxide and water vapor.

Practice Problems: Oxidation vs. Reduction

When a metal is oxidized, it means that the metal has lost electrons. This usually happens when the metal comes into contact with oxygen. The opposite of oxidation is reduction, which is when a metal gains electrons. This can happen when the metal comes into contact with another element, like hydrogen. In both cases, we are talking about how metals react to other elements in their environment. For example, iron will rust when exposed to water and air.

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The process of rusting is an example of oxidation because iron loses electrons and becomes less electrically charged (less electronegative). In this case, the iron is losing its electrons so it becomes more electronegative. If you were to cut open the rusted piece of iron, you would see an orange or reddish color on the inside where the atoms have been displaced by oxygen. Electrons are often transferred from one atom to another as they bond together and form molecules. In this case, one atom gives up an electron while the other takes on two new ones!


In a nutshell, oxidation is the loss of electrons and reduction is the gain of electrons. When one substance undergoes oxidation, another substance must undergo reduction. Oxidation and reduction always occur together and they are known as redox reactions.