Chapter 18, Problem 8A

Interpretation Introduction

Interpretation: The sum of all the oxidation state of atoms in ${\text{SO}}_{\text{4}}{}^{2-}$ needs to be determined.

Concept introduction: The change in oxidation state explains the loss and gain of electrons in oxidation−reduction reactions.

Answer to Problem 8A

In ${\text{SO}}_{\text{4}}{}^{2-}$ sum of all oxidation states of all the atoms is -2.

Explanation of Solution

In ${\text{SO}}_{\text{4}}{}^{2-}$ oxidation state of S is +6 and oxidation state of four oxygen atoms is -8 $\left(-2\times 4=-8\right)$ .

Thus overall oxidation state of ${\text{SO}}_{\text{4}}{}^{2-}$ is as follows:

$\begin{array}{c}{\text{SO}}_{\text{4}}{}^{2-}=6-8\\ =-2\end{array}$

Conclusion

Loss of electrons is oxidation and gain of electrons is reduction.