Key difference: Oxidation and reduction are two processes that occur in a redox reaction. In oxidation, a molecule, atom, or ion experiences an increase in oxidation state or basically, it looses electrons. In reduction, a molecule, atom, or ion experiences a decrease in oxidation state, or rather it gains electrons.

Oxidation and reduction are two processes that occur in a redox reaction. Redox stands for reduction-oxidation. It is essentially a reaction, in which ‘atoms have their oxidation state changed’. An easier way to say this is that the reaction involves the transfer of electrons between two or more molecules.

In oxidation, a molecule, atom, or ion experiences an increase in oxidation state or basically, it looses electrons. Reduction is essentially the opposite of that. In reduction, a molecule, atom, or ion experiences a decrease in oxidation state, or rather it gains electrons.

Oxidation and reduction always occur simultaneously. This is mainly because when the molecule, atom, or ion looses an electron; the electron must go somewhere; i.e. to another molecule, atom, or ion. This molecule, atom, or ion, in turn gains the electron that was lost.

Let us consider an example:

H₂ + F₂ → 2 HF

Let us break these down to atoms and ions:

H₂ → 2 H⁺ + 2 e−

The hydrogen molecule looses two electrons to become two hydrogen ions. This is essentially the oxidation reaction, as it involved the loss of electrons.

F₂ + 2 e⁻ → 2 F⁻

The fluorine gains the two electrons lost by the hydrogen molecule to become two fluorine ions. This is essentially the reductions reaction, as it involved the gain of electrons.

2 H⁺ + 2 F⁻ → 2 HF

The two hydrogen ions and the two fluorine ions come together to form two molecules of hydrogen fluoride.

Hence, the entire redox reactions can be written as:

H₂ + F₂ → 2 HF

While, oxidation and reduction occur on a molecule or atom level, it is still possible to see examples redox reactions in our daily lives. Some examples of a redox reaction are the rusting of iron; the browning of an apple; bleach breaking down stains, etc. 

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