Concept of Oxidation - Example and Oxidizing Agents

Concept of Oxidation is a process in which a chemical species loses one or more electrons, leading to an increase in its oxidation state.
In simpler terms, the species becomes more positively charged.
Oxidation is often associated with the addition of oxygen to a substance or the removal of hydrogen from it.
However, the key factor that defines oxidation is the loss of electrons.

Consider the reaction between magnesium metal (Mg) and oxygen gas (O₂) to form magnesium oxide (MgO).
- Mg (s) + 12O₂ (g) → MgO (s)
In this reaction, magnesium loses two electrons to become the Mg²⁺ ion, as shown below:
- Mg (s) → Mg²⁺ (s) + 2e−
Magnesium has been oxidized, as it has lost electrons, and its oxidation state has increased from 0 to +2.

An oxidizing agent is a substance that gains electrons in a redox reaction, causing the oxidation of another species.
By accepting electrons from another species, it enables that species to lose electrons, leading to its oxidation.
As a result, the oxidizing agent itself gets reduced in the process. Oxidizing agents typically have a high affinity for electrons and can be identified by their ability to oxidize other substances.
Example:
- In the reaction between hydrogen gas (H₂) and oxygen gas (O₂) to form water (H₂O):
  - 2H₂ (g) + O₂ (g) → 2H₂O (l)
- Oxygen (O₂) is the oxidizing agent, as it gains electrons from hydrogen (H₂) during the reaction, leading to the reduction of oxygen and the oxidation of hydrogen.