Chapter 22, Problem 3STP

Interpretation Introduction

Interpretation:

The oxidation numbers of the elements in ${\text{CuSO}}_{\text{4}}^{}$ needs to be determined.

Concept introduction:

In a chemical combination, oxidation number is defined as number that is assigned to an element that represents the number of electrons gained or lost by an elements’ atom in compound.

Answer to Problem 3STP

Correct Answer: Option (a)

Explanation of Solution

Reason for correct option: The given compound is ${\text{CuSO}}_{\text{4}}^{}$. It is an ionic compound which dissociates as follows:

${\text{CuSO}}_{\text{4}}^{}\to {\text{Cu}}^{2+}+{\text{SO}}_{\text{4}}{}^{2-}$

Thus, the oxidation number of Cu is +2.

Generally, the oxidation number of O is -2. Therefore, the oxidation number of S can be calculated as follows:

${\text{SO}}_4^{2-}$

Let the value be x thus,

$x+4\left(-2\right)=-2$

On calculating,

$\begin{array}{c}x+4\left(-2\right)=-2\\ x-8=-2\\ x=-2+8\\ =+6\end{array}$

Thus, the oxidation number of S is +6.

Therefore, the oxidation number of Cu is +2, S is +6 and O is -2. The correct option is (a).