How To Find Redox Reaction: Redox Reaction Process And Facts Around It


Redox reaction plays an important role to run various biological processes in living body. In this article, “how to find redox reaction” different facts about redox reaction, with definition and some detailed explanations are described below-

Among different type of chemical reactions, redox reaction is one of them. Electron transfer from one species to another drive the reaction towards forward direction. During this reaction one or more than one electron is transferred from oxidized species to reduced species.

Some frequently asked questions about redox reaction are answered below.

How to do a redox reaction?

The following steps must be followed to execute a redox reaction-

  1. At the first stage the oxidation and reduction half reaction must be determined from the net redox reaction.
  2. Number of electrons gained or lost by each species should be calculated.
  3. Multiply the half reactions with a suitable integer to equal the no of electrons in each half reaction.
  4. These two halves reaction will be added with each other to obtain the final balanced redox reaction.

Define redox reaction

The term “redox” signifies reduction and oxidation simultaneously. Oxidation number and oxidation state are changed in redox reaction by transferring of electrons.

Oxidizing agent, accepts electron from other species and reducing agent, donates electron to oxidizing agent are two important parts of redox reaction. Reducing agent and oxidizing agent are oxidized and reduced in the redox reaction respectively.

How to determine redox reaction?

Redox reaction must involve the change of oxidation number between two species taking part in the reaction. Oxidizing agent of any redox reaction accepts electrons and its oxidation number should be decreased. Similarly, the oxidation number of the reduced species should be decreased.

how to find redox reaction
Redox Reaction.
Image Credit: Wikimedia Commons

Redox reaction formula

Redox Reaction.
Image Credit: Wikimedia Commons

In this above example, Fe2+ is oxidized to Fe3+ and Ce4+ is reduced to Ce3+ respectively. In the net balanced equation is clear that Ce4+ is an oxidizing agent which is reduced by Fe2+ and similarly, Fe2+ is a reducing agent which is oxidized by Ce4+.

How to find moles of electrons in redox reaction?

Through a redox reaction one or more than one electron can be are transferred from oxidizing agent to reducing agent. Balanced equation helps to find out the number or mole number of electrons of a redox reaction. Let assume one example to clear this problem.

I2 (s) + Fe (s) Fe3+ (aq) + 2I (aq)

  • Reduction half reaction: I2 +2e 2I   ———1 no equation                                                                
  • Oxidation half reaction: Fe Fe3+ + 3e ——-2 no equation
  • 1 no equation× 3)——— 3I2 +6e 6I 
  • 2no equation × 2)———–2Fe 2Fe3+ + 6e– 
  • Net balanced equation is: 3I2 + 2Fe 6I+ 2Fe3+

In this above example, six electrons are involved. Thus, number of moles of electrons are 6/(6.023×1023) = 9.96×10-24

To know more please check: 4 Hydrogen Bond Examples : Detailed Insights And Facts

How to find the oxidation number in a redox reaction?

Oxidation number of each species involved in redox reaction can be determined from balanced redox equation. Let assume one example–                                                           

Cu + 2NO3 +4H3O+ Cu2+ + 2NO2 +6H2O                                         

Oxidation number of respective species are written on the above of each species. Oxidation number of Cu is increased from 0 to 2. Thus, it is oxidized and reduces N because oxidation number of nitrogen is decreased from 5 to 4. Oxidation number of rest of the compounds remain constant.

How to find the reducing agent in a redox reaction?

At first the half net reaction must be determined from a net balanced redox equation. Redox reaction generally consists of two types of different species such as oxidizing agent and reducing agent.

In redox reaction, the substance gains electron and oxidation number is decreased is called oxidizing agent. The species loses electron and oxidation number of that species is increased is known as reducing agent.

In the following reaction-

MnO4 + SO32- Mn2+ + SO42-                                         MnO4 is oxidizing agent and SO32- is reducing agent respectively.

How to find delta g of a redox reaction?

Delta G determines the spontaneity of any reaction. Negative value of ΔG directs the reaction towards spontaneous reaction and positive value favours the backward direction.

Electrode potential plays an important role to determine the change of Gibbs free energy. ΔG0 = -nFE0cell. E0Cell= E0Reduction – E0oxidation. [n= number of electrons involved in the redox reaction, F = Farade constant= 96500 coloumb]. Electrode potential should be positive to run any reaction spontaneously.

To know more please check: Function of peptide bond: detailed fact and comparative analysis

How to find the net ionic equation of a redox reaction?

Let’s take an example of an unbalanced redox equation and see the steps to balance the equation.

Fe2+ +MnO4 → Fe3+ + Mn2+

  • Oxidation half reaction: Fe2+= Fe3+ + e  ——–1 no equation                                                         
  • Reduction half reaction: MnO4 + 8H+ = Mn2+ + 4H2O + 5e——2 no equation
  • 1no equation × 5)——— 5Fe2+ = 5Fe3+ + 5e
  • 2no equation ×1)———MnO4 + 8H+ = Mn2+ + 4H2O + 5e
  • Net balanced equation is—— 5Fe2+ + MnO4 + 8H+ = 5Fe3+ + Mn2+ + 4H2O

How to find the products of a redox reaction?

The products obtained from a redox reaction depends only on the reagents that are taken. In a redox reaction, main reactants that are present are oxidizing and reducing agent

The products are obtained either oxidized or reduced product. Not only the reactant, nature of the reaction medium also determines the products. Acidic and basic medium give different products after using the same reactant for both of these medium.

How to find equivalent weight in redox reactions?

Equivalent weight is calculated dividing molecular weight of any compound by the number of electrons involved in that particular reaction.

To calculate the equivalent weight of any reactant or product the following steps must be followed.

  1. Determine the molecular weight of the substance.
  2. Calculate the number of electrons involved in the redox reaction.

For an example-

5Fe2+ + MnO4 + 8H+ 5Fe3+ + Mn2+ + 4H2O                                                      Equivalent weight of Fe = 55.845 amu/5 =11.169 amu.

To know more please go through: CH2CL2 Lewis Structure Why, How, When And Detailed Facts

How to find number of electrons transferred in redox reaction?

At first stage, oxidation and reduction half reaction must be separated. Then the electrons involved each of the reactions will be determined.  In oxidation half reaction electrons are lost and in the time of reduction half reactions electrons are gained by respective compounds.

The least common number of the two integers (no of electrons from each of the half reaction) is the number of electrons transferred in the redox reaction.

  • Mg Mg2+ + 2e(oxidation half reaction)
  • Al3++ 3e Al (reduction half reaction
  • Least common number of 2 and 3 is 6. Thus, no of electrons transferred in this redox reaction is 6.

Are electrons transferred in redox reactions?

Without transferring electrons, redox reaction cannot take place. Transferring electrons from one species to another species is the key point of any redox reaction.

Electrons are transferred from reducing agent or oxidized species to the oxidizing agent or reduced species and the reaction proceeds towards forward direction. If electrons are not transferred from reducing agent to oxidizing agent the reaction can no take place products cannot be obtained.

To know more please follow: Is HBr Ionic or Covalent : Why? How, Characteristics and Detailed Facts

How is combustion a redox reaction?

Combustion is one type of chemical reaction in which any chemical species is burnt in presence of molecular oxygen at high temperature and most of the time oxidized gaseous products are obtained as product. Combustion reaction proceeds through an exothermic reaction pathway as a huge amount of energy is released in progress of the reaction.

For an example of combustion reaction-

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

In the above example of combustion reaction, methane (CH4) gas is burnt with the help of oxygen and carbon dioxide with water is obtained as products.  Combustion is definitely a redox reaction in which oxygen is oxidizing agent and methane is oxidized so it is reducing agent.

Aditi Roy

Hello, I am Aditi Ray, a chemistry SME on this platform. I have completed graduation in Chemistry from the University of Calcutta and post graduation from Techno India University with a specialization in Inorganic Chemistry. I am very happy to be a part of the Lambdageeks family and I would like to explain the subject in a simplistic way. Let's connect through LinkedIn-https://www.linkedin.com/in/aditi-ray-a7a946202

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