Difference between Oxidation and Reduction

Types of Chemical Reactions: Oxidation and Reduction Reactions 

Introduction: 

Displacement & Double Displacement: 

Reactions in which one element displaces the other with low reactivity are single displacement or displacement. Reactions in which two reactants exchange their elements or ions and form two products are double displacement. Displacement reaction is also called replacement reaction as the element is replaced in the case. If one element is replaced, then we call it the single replacement, and if two elements are replaced, we call them the double replacement reactions. 

Explanation: 

Oxidation Reaction: 

An element that loses electrons or hydrogen, or gains oxygen, undergoes oxidation and the element is said to be oxidised. The loss of electrons is called the oxidation of the atom or element. Take an example to understand oxidation. 

Cu²⁺    +    Mg    →    Cu    +   Mg²⁺ 

Here, Mg is losing two electrons to attain the state of Mg²⁺. The loss of electrons is called oxidation.  

Reduction Reaction:  

An element that gains electrons or hydrogen, or loses oxygen, undergoes reduction and the element is said to be reduced. The gain of electrons is called the reduction of the atom or element. Take an example of understandable reduction.  

Cu²⁺    +    Mg    →    Cu    +   Mg²⁺ 

Here, Cu²⁺ is gaining two electrons to attain the state of Cu. The gaining of electrons is called reduction.  

Redox Reaction:  

A reaction in which oxidation and reduction take place simultaneously is said to be a redox reaction. Oxidation and reduction always happen simultaneously in a reaction. Take the same example discussed so far.  

Cu²⁺    +    Mg    →    Cu    +   Mg²⁺ 

In this equation, we see the gaining of the electrons and the closing of the electrons simultaneously. Copper is gaining electrons and magnesium is losing electrons. Let us see some other examples as well for a better understanding.  

Fe₂O₃    +    3CO    →     2Fe    +     3CO₂ 

If we observe, here Ferrum or iron is losing electrons and is reducing, whereas CO is gaining the electrons as the oxygen and is oxidized. Since both oxidation and reduction are taking place at the same time the reaction is a redox reaction.  

Reductant:  

A substance that undergoes oxidation and helps the other substance to undergo reduction is said to be a reductant or reducing agent.  

Zn     +     Cu²⁺     →     Zn²⁺     +     Cu 

Clearly, we see that Zn is losing the electrons and the reduction. Since, the Zn is reduced we call it as the reducing agent or the reductant.  

Oxidant:  

A substance that undergoes reduction and helps the other substance to undergo oxidation is said to be an oxidant or oxidising agent.  

Zn     +     Cu²⁺     →     Zn²⁺     +     Cu 

Clearly, we see that Cu²⁺ is gaining electrons and the oxidation has occurred. Since, the Cu is oxidised we call it as the oxidising agent or the oxidant.  

Activity:  

Take a China dish and place Copper powder in it.   

Place a tripod on it and wire gauze above it.  

Heat the substance in the China dish with a Bunsen burner.   

Observations:  

On heating the copper powder, we observe the brown powder turning to black colour.  

Identifying the Oxidant and Reductant:  

Let us take an example of the Redox reaction:  

Copper is reductant as the change in oxidation number is 0 to +2   

Oxygen is oxidant as the change in oxidation number is 0 to -2  

There are different types of the Redox reactions and they are:  

• Combination  
• Decomposition  
• Displacement  
• Disproportionation  

Redox – Combination Reaction:  

In the Chemical equation   

3Mg(s)     +    N₂(g)    →    Mg₃N₂(s) 

Magnesium is reductant and Nitrogen is oxidant. Here two elements are combining to form the compound.  

Redox – Decomposition Reaction:  

In the chemical equation  

2 CuBr    →    CuBr₂    +    Cu 

Copper is reductant and Bromine is oxidant. One single compound is getting divided into two parts.  

Redox – Displacement Reaction:  

In the chemical equation  

Mg     +    HCl     →    MgCl₂    +    H₂ 

Here, Hydrogen is displaced.  

Redox – Disproportionation Reaction:  

In the chemical equation  

2H₂O₂     →     2H₂O      +      O₂ 

The reaction in which one substance undergoes both oxidation and reduction. Oxygen is reductant and hydrogen is oxidant.  

Differences of Oxidation and Reduction:  

Summary

1. The reaction in which both oxidation and reduction take place together is redox reaction.
2. Oxidation is loss of electrons and reduction is gain of electrons.
3. A substance that undergoes oxidation and helps the other substance to undergo reduction is said to be a reductant or reducing agent.
4. A substance that undergoes reduction and helps the other substance to undergo oxidation is said to be a oxidant or oxidising agent.
5. Redox reaction can be of four types: Combination, displacement, decomposition and disproportionation reactions.