Question

Name the reaction in which one of the reacting species loses electrons while the other gains electrons:

Answer 1

The species that lose electrons undergo oxidation. The species which gains electrons undergo reduction. Both oxidation and reduction can occur simultaneously in a reaction. Thus two half-reactions involving oxidation and reduction can occur in a chemical reaction.

Complete step by step answer:
The reaction in which reacting species loses electrons is oxidation.
The reaction in which reacting species gains electrons is reduction.
When both oxidation and reduction take place simultaneously in a chemical reaction it is called reduction-oxidation reactions or redox reactions.
Therefore redox reactions are reactions where both oxidation and reduction take place.
So the reaction in which one of the reacting species loses electrons and the other reacting species gains electrons is called the redox reactions.
Thus the answer to the question is redox reactions.
Let’s look at an example of a redox reaction:
$2N{a_{(s)}} + {H_2}_{_{(g)}} \to 2Na{H_{(s)}}$ is a redox reaction where sodium is oxidized and hydrogen is reduced.
The oxidation half-reaction when sodium loses electrons are shown below:
$2N{a_{(s)}} \to 2N{a^ + }_{(g)} + 2{e^ - }$
The reduction half-reaction where hydrogen gains electrons are shown below:
${H_2}_{_{(g)}} + 2{e^ - } \to 2{H^ - }_{(g)}$.
Redox reactions are otherwise called reduction-oxidation reactions.
Oxidation and reduction reactions involve the exchange of electrons.
Thus we can say redox reactions are reactions in which simultaneous transfer of electrons takes place from one reacting species to the other reacting species.
There are different forms of definitions for oxidation and reduction.
Oxidation can be defined as the addition of oxygen to a species or removal of hydrogen from a species.
Or we can say oxidation is the loss of electrons from a species.
Similarly, the reduction can be defined as follows:
The reduction is the addition of hydrogen to a species or removal of oxygen from a species.
Or reduction is the gain of electrons by a chemical species.
Thus in redox reactions, half-reactions that involve loss of electrons are oxidation and the other half-reactions involve gain of electrons called reductions.

Note:
Oxidation is an increase in the oxidation number of a species and reduction is a decrease in the oxidation number of a species. Thus redox reactions are reactions that involve a change in the oxidation number of the reacting species. The species which accept electrons are called the oxidizing agent and the species that donate electrons is the reducing agent.