Chapter 14, Problem 1QC

Interpretation Introduction

Interpretation:

Oxidation-reduction reaction is to be explained.

Concept Introduction:

The reaction in which reduction of a substance and oxidation of other substance takes place, is known as redox or oxidation-reduction reaction.

Explanation of Solution

In a oxidation-reduction reaction, the oxidation state of a substance increases due to loss of electrons and hence gets oxidized, and oxidation state of other substance decreases due to gain of electrons and hence gets reduced.

For example, the oxidation-reduction reaction along with the oxidation states of each element present in reactants and products is as follows:

$4\stackrel{0}{\text{Al}}\left(s\right)+3\stackrel{0}{{\text{O}}_2\left(g\right)}\to 2\stackrel{3+}{{\text{Al}}_2}\stackrel{2-}{{\text{O}}_3}\left(s\right)$

The oxidation state of $\text{O}$ decreases from $0$ to $2-$ and that of $\text{Al}$ increases from $0$ to $3+$ . So, the substance oxidized is $\text{Al}\left(s\right)$ and reduced is ${\text{O}}_2\left(g\right)$ .

Conclusion

Increase in the oxidation state of a substance represents oxidation and decrease in the oxidation state of a substance represents reduction reaction.