Electron transfer In Oxidation And Reduction

What is oxidation?

We get to hear the terms like oxidation and reduction a lot in CBSE class 12th Chemistry and to be precise, oxidation means gaining oxygen in a chemical reaction We will be looking at oxidation and reduction from two different points of view.

  • Oxidation and Reduction in terms of Oxygen transfer
  • Oxidation and Reduction in terms of electron transfer

What is Reduction?

In Chemistry, it is referred to the loss of oxygen when it is with respect to the oxygen transfer. It is the job of the reducing agent to remove the oxygen from another substance. Similarly, in case of hydrogen transfer, it is the gain of hydrogen. That means, it is reducing agent’s work to remove oxygen from one substance and hydrogen to it.

Oxidation and Reduction in terms of Oxygen transfer

In early chemistry, oxidation and reduction were terms associated with oxygen. Oxidation meant gaining oxygen and Reduction meant losing oxygen. The term ‘reduction’ comes from Latin and means ‘-to lead back’. Therefore anything that leads back to the free metal state is referred to as a reduction reaction.

Magnesium undergoes both oxidation and reduction in reactions with different reactants.

Oxidation And Reduction

Oxidation and Reduction in terms of Electron transfer

This is the most commonly used definition of oxidation and reduction and most widely applicable. In this case, Oxidation is the loss of electrons and Reduction is the gain of electrons. A very clever mnemonic to remember this concept is oil rig.
 OIL                                 RIG
Oxidation is loss          Reduction is gain

Oxidation and Reduction reactions are always interlinked. Because electrons are neither created nor destroyed in a chemical reaction, oxidation and reduction always occur in pairs, it is impossible to have one without the other. In the below reaction Magnesium gets oxidized by losing two electrons to oxygen which gets reduced by accepting two electrons from magnesium.

Oxidation And Reduction

Since oxidation and reduction cannot occur individually, they as a whole are called  ‘Redox Reactions’. The reactant that oxidizes the other reactants is called as the Oxidizing agent and reactant that reduces is called Reducing agent. There is quite some confusion about the aspect whether oxidizing agents accept or give away electrons.
The following steps can help you figure it out.

  • An oxidizing agent oxidizes the other reactants
  • This must mean that the oxidizing agent is getting reduced
  • Oxidation is loss of electrons (OIL RIG)
  • So an oxidizing agent must gain electrons

So remember that oxidation means loss of electrons but an oxidizing agent gains electrons. Such complicated concepts are made simple through conceptual learning at BYJU’s.

Practise This Question

Assertion – The non-fusible impurities present in iron ore are removed by CaCO3 .

Reason: CaCO3 which decomposes into CaO and CO2. The CaO formed reacts with SiO2 to remove silica