Redox reactions : The simultaneous Oxidation Reduction Reactions

Chemistry, in general, is the study of changes around us. Our world is full of continuous transformations. Some of these changes are easy to perceive while some of them remain unnoticed. Processes such as photosynthesis, respiration, combustion of fuels, corrosion and rusting of iron occur evidently around us. Chemistry is all about the transformation of matter from one form to another and the factors governing these transformations. There is a wide variety of chemical reactions through which this transformation takes place. Redox reaction is one of the most important classes of chemical reactions in chemistry. It has been seen that oxidation and reduction reactions always occur simultaneously, such class of chemical reactions was named as redox reactions or called as Oxidation-Reduction Reactions.

Redox reactions

Redox reactions Halves

Redox reactions Halves

In order to understand redox reactions, let us first deal with oxidation and reduction reactions individually.

  • What Is Oxidation Reaction?

Oxidation may be defined as loss of electrons from a substance, the other definition of oxidation reactions states that addition of oxygen or the more electronegative element or removal of hydrogen or the more electropositive element from a substance is called as an oxidation reaction. Following are some examples of oxidation reactions:

2S(s)      +     O2 (g)   →   SO2 (g)

CH4 (g)  +    2O2 (g)   →   CO2 (g)   +   2H2O (l)

  • What is Reduction Reaction?

Like oxidation reactions, reduction reactions are defined as the gain of electrons. Any substance that gains electron during a chemical reaction gets reduced. In other forms, the reduction reaction is stated as the addition of hydrogen or more electropositive element or removal of a more electronegative element or oxygen from a substance. Below are some examples of reduction reactions:

2CH2CH2 (g)    +     H2 (g)     →     CH3CH3 (g)

2FeCl3 (aq)      +     H2 (g)    →    2FeCl2 (aq)    +   2HCl (aq)

Now if we closely examine the above reaction we would find that all the reactions above have both, reduction and oxidation reactions. The reaction in which FeCl3 is getting reduced as an electronegative element chlorine is being removed from it. While hydrogen is getting oxidized due to the addition of chlorine, an electronegative element, in the same reaction.

In a chemical reaction, if a substance is getting oxidized that means it is losing electrons, these electrons must be taken by some other substance in order to balance the reaction. Hence there is a substance that gains these electrons and hence gets reduced. So oxidation and reduction reactions always occur simultaneously and are called redox reactions or Oxidation-Reduction Reactions. The substance getting reduced in a chemical reaction is known as the oxidizing agent, while a substance that is getting oxidized is known as the reducing agent.

Redox reactions are one of the most important classes of chemical reactions and their application in various industries is quite visible. Electrochemistry is one of the many fields where the application of Oxidation-Reduction Reactions for generating electrical energy from chemical reactions or carrying out a non-spontaneous reaction with the help of electricity has become common. Get in touch with our mentors for any further doubts. Keep learning.

Practise This Question

A chemical reaction XY is said to be in equilibrium when -