In a redox reaction, oxidation and reduction must occur simultaneously. The exchange of electrons is the basic requirement of any redox reaction. But in an oxidation reaction, a reactant is oxidized in the presence of oxygen or any oxidizing agent to obtain an oxidized product.
Let us discuss some frequently asked questions along with the answers to these two responses below.
How is oxidation a redox reaction?
Redox reaction involves two separate half reactions which take place simultaneously in a single redox reaction-
- oxidation half reaction
- Half reaction reduction.
The exchange of electrons between two reactants is the most important criterion to be fulfilled in a redox reaction. These two reactants are basically oxidised and reduced together with the help of another reactant. In the reduction half-equation, the reactants must gain electrons and in the oxidation half-reaction, the reactant must lose electron(s) to obtain the corresponding product. The number of electrons gained or lost during the redox reaction must be properly balanced to obtain the correct balanced redox equation.
Fe 2+ + MnO 4 – → Fe 3+ + Mn 2+ (unbalanced redox equation)
- Oxidation half-reaction: Fe 2+ → Fe 3+ and – ——–1 No equation
- Reduction half reaction: MnO 4 – + 8H + → Mn 2+ + 4H 2 O + 5e – ——2 No equation
- (1no equation ×5)——— 5Fe 2+ → 2 Fe 3+ + 5e –
- (2no equation ×1)————MnO 4 – + 8H + → Mn 2+ + 4H 2 O + 5e –
- The net balanced equation is—— 5Fe 2+ + MnO 4 – + 8H + → 2 Fe 3+ + Mn 2+ + 4H 2 O
Oxidation reaction basically signifies the loss of electron by any of the reactants in the presence of an oxidizing agent. On reacting with oxygen, the oxidation number of that reactant also increases. The loss of hydrogen from any substance is also an example of an oxidation reaction.
- 2Mg + O 2 → 2MgO (reaction with oxygen)
- CH 3 CH 2 CHO → CH 3 CHO (loss of hydrogen)
Are all oxidation reactions redox?
The redox reaction is known as the oxidation-reduction reaction. A redox reaction can be divided into two half reactions i.e. oxidation and half reaction. So, the oxidation reaction must be involved in the redox reaction.
In an oxidation reaction, reactants react with oxygen and the oxidation number of that particular species increases in the product compared to that of the reactant. With this the oxidation number of oxygen or any other oxidizing reagent in the product by which the substance is oxidised is reduced. Therefore, in any reaction, only oxidation can take place separately.
There are generally two reactants present in a redox reaction. Electrons are exchanged or transferred from one reactant to another and obtained as an oxidation product with a reduced species.
In this above example, Fe . The oxidation number of Fe is 2 O 3 +3 which is changed to 0 on the product side. Thus, this reduction of carbon in half reaction and oxidation number of carbon is +2 in CO but it is changed to CO. In +4 is converted to 2 . So, this oxidation is part of the half-reaction.
Let us balance the above equation-
The change of oxidation number for the oxidation half-reaction and reduction half-reaction are 2 and 3 respectively. Thus, the net balanced equation is-
Fe 2 O 3 + 3 C O → 2Fe + 3CO 2
What happens in redox reaction?
Redox reaction is nothing but electron transfer between two substances. One reactant is oxidised and the other reactant is reduced due to the exchange of electrons. In oxidation process, the reactant loses its electrons whereas in reduction, the reactant gains electrons in a single redox reaction.
Let us take an example to make it clear-
Zn (s) + 2H + (aq) + 2Cl – (aq) → H 2 (g) + Zn 2+ (aq) +2Cl – (aq)
In this above example, Zn is oxidized to Zn 2+ and has lost two electrons and the oxidizing agent H. is + . So, the oxidation half-reaction is: Zn(s) → Zn 2+ (aq). Similarly, H + H . is reduced to 2 by taking two electrons with the help of Zn. Thus, Zn acts as a reducing agent and H + acts as an oxidising agent. The reduction half equation will be 2H + (AQ) → H 2 (g)
What happens in an oxidation reaction?
Oxidation reaction is nothing but increase in oxidation number or decrease of one or more electrons. The oxidation state increases with time of oxidation.
It is not always certain that oxidation can occur only in the presence of oxygen, any other oxidizing agent may take part in the oxidation reaction. The purpose of adding oxygen or an oxidizing agent is to accept electrons that are donated by the reactant to obtain an oxidized product. Reverse reaction of oxidation is reduction which is nothing but gain of electrons.
Let us take an example of an oxidation reaction-
Iron reacts with oxygen to form the oxidized product iron oxide (Fe. 2 O 3 ).
4Fe + 3O 2 → 2 Fe 2 O 3
Redox Reaction vs Oxidation
|redox reaction||oxidation reaction|
|Redox reaction is basically the exchange of electrons between two participating atoms, molecules or ions.||Oxidation is nothing but the donating or losing of electrons to oxygen or some other oxidizing agent.|
|The redox reaction consists of two opposite half reactions, the oxidation half reaction and the half reaction.||In oxidation reduction, a reactant is oxidised with the help of oxygen and forms an oxidized product.|
|An example of a redox reaction is: 2HNO 3 + 3H 3 AsO 3 (AQ) → 2NO (G) + 3H 3 AsO 4 (AQ) + H 2 O (L).||An example of an oxidation reaction is: 2Mg + O 2 → 2MgO .|
Relationship Between Redox Reactions and Oxidation Reaction
In a redox reaction, reduction and oxidation occur at the same time. The oxidizing agent (oxidizes other chemical species) accepts reducing electrons from the reducing agent (reduces another). Basically, it is an electron transfer reaction. Oxidized species lose electrons and reduced species gain electrons in redox reactions, thus, redox reactions can be divided into two parts—oxidation and reduction half reactions.
process, oxidation must be present in a redox reaction.
In this above example, Ce 4+ Ce . is reduced to 3+ and Fe 2+ gets oxidized to Fe 2+ gets oxidized to Fe 3+ . The above reaction is an example of a redox reaction because both oxidation and reduction are involved in this reaction through the transfer of electrons between two reactants.