Question

Reduction is a process in which:
This question has multiple correct options
A.Gain of electrons take place
B.Oxidation number is reduced
C.Oxidation number is increased
D.Loss of electrons takes place

Answer 1

Term reduction means getting reduced. It is a type of chemical reaction involving the transfer of electrons. The species which undergo reduction is called an oxidizing agent. If an element is reduced, it is known as a reduction.

Complete step by step answer:
As we already know reduction is a process in which the element gets reduced.
An element gets reduced which means that electrons are gained by the element which has a higher reduction potential.
This is because any loss of electrons by any substance (oxidation) is accompanied by the gain of those electrons and it is called reduction.
Let us take an example to understand it more clearly.
${\text{C}}{{\text{u}}^{{\text{2 + }}}}{\text{ + Mg}} \to {\text{M}}{{\text{g}}^{{\text{2 + }}}}{\text{ + Cu}}$
Here we can see that ${\text{C}}{{\text{u}}^{{\text{2 + }}}}$ gain the electron released by Mg to form Cu. Thus, it is a reduction reaction that involves the addition of electrons that are released during oxidation.
${\text{C}}{{\text{u}}^{{\text{2 + }}}}{\text{ + 2}}{{\text{e}}^{\text{ - }}} \to {\text{Cu}}$ is a reduction. ${\text{C}}{{\text{u}}^{{\text{2 + }}}}$ acts as the oxidizing agent.
Now let us look at the oxidation number. ${\text{C}}{{\text{u}}^{{\text{2 + }}}}$ has an oxidation number +2, whereas the Oxidation number of Cu is Zero.
From the above step, we can conclude that on reduction, the oxidation number is reduced.
We know that reduction is the gain of electrons.
So, Reduction is a process in which electrons are gained and the oxidation number is reduced.
Now, let us check the options. Option A is the gain of electrons that is correct. Option B's oxidation number is reduced which is also correct.
Thus, the correct options are (A) and (B).

Note: Oxidation is when a substance donates electrons. ${\text{Mg}} \to {\text{M}}{{\text{g}}^{{\text{2 + }}}}{\text{ + 2}}{{\text{e}}^{\text{ - }}}$. Here, the oxidation number is increased from 0 to 2. Thus, oxidation is the opposite of reduction in which loss of electrons takes place and the oxidation number is increased. By knowing the electrochemical series and standard electrode potential values, it is easy to know which substance is getting reduced and which act as an oxidizing agent.