Nilesh Khartad

Originally oxidation reactions were identified as the reactions in which oxygen gas participates. There, oxygen combines with another molecule to produce an oxide. In this reaction, oxygen undergoes reduction and the other substance undergoes oxidation. Therefore, basically, the oxidation reaction is adding oxygen to another substance. For example, in the following reaction, hydrogen undergoes oxidation and, therefore, oxygen atom has added to hydrogen forming water. 2H2 + O2 -> 2H2O Another way to describe oxidation is as loss of hydrogen. There are some occasions where it is hard to describe oxidation as adding oxygen. For example, in the following reaction, oxygen has added to both carbon and hydrogen, but only carbon has undergone oxidation. In this instance, oxidation can be described by saying it is the loss of hydrogen. As hydrogens have removed from methane when producing carbon dioxide, carbon there has been oxidized. CH4 + 2O2 -> CO2 + 2H2O Another alternative approach to describing oxidation is as losing of electrons. This approach can be used to explain chemical reactions, where we can’t see an oxide formation or hydrogen losing. So, even when there is no oxygen, we can explain oxidation using this approach. For example in the following reaction, magnesium has converted to magnesium ions. Since magnesium has lost two electrons it has undergone oxidation and chlorine gas is the oxidizing agent. Mg + Cl2 -> Mg2+ + 2Cl- Combustion or heating is a reaction where heat is produced by an exothermic reaction. For the reaction to take place, a fuel and an oxidant should be there Combustion is an oxidation reaction. • For combustion, the usual oxidant is oxygen but, for an oxidation reaction to take place, oxygen is not essential. • In combustion, the products are primarily water and carbon dioxide but, in oxidation, the product can vary depending on the starting material. However, always they will have a higher oxidation state than the reactants. • In combustion reactions, heat and light are produced, and work can be done from the energy. But for oxidation reactions, this is not always true.