Redox Reactions

What is Redox?

Redox or Reduction and Oxidation are a pair of chemical reactions that occur together.

Oxidation was originally observed when elements combined with oxygen to form oxide compounds.

The reverse reaction of oxidation is reduction. Instead of adding oxygen the amount of oxygen in a compound is reduced.

This oxidation reaction is commonly known as rusting

There are many other common examples of oxidation:

Bleach oxidizes stains to colorless compounds
Fire oxides fuel to carbon dioxide
Apple slices turning brown

General definition of Oxidation and Reduction

Oxidation Is a Loss of electrons and Reduction Is a Gain of electrons.

OIL RIG

Loss of Electrons is Oxidation and Gain of Electrons is Reduction

LEO says GER

Oxidation and reduction are always paired in a reaction. One reactant gives up electrons while one receives electrons

With ionic compounds it is easy to tell what chemical is reduced/oxidized by looking at the charges of the ions.

In the reaction above:

Fe (neutral) → Fe3+ (loss/oxidation)
O (neutral) → O2- (gain/reduction)

The chemical that loses electrons is called the reducing agent because it causes reduction in the other chemical.

In the reaction above iron (Fe) was the reducing agent

The chemical that gains electrons is called the oxidizing agent because it causes oxidation in the other chemical.

In the reaction above oxygen (O) was the oxidizing agent

Corrosion

Rust is bad for metal because oxides are often weaker than the pure metal. But the oxidation process can also dissolve the metal into ions. This can weaken metal objects like cars or steel bridges.

Oxidation needs two things:

Water
Oxygen

Covering the metal in paint or a non-reactive material will prevent the water and oxygen from coming in contact with the metal.

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