Chapter 23, Problem 89A

a)

Interpretation Introduction

Interpretation : To determine the oxidation state of nitrogen in ${\text{NaNO}}_{\text{2}}$

Concept Introduction : The oxidation state of any element is the ability of the element to gain or lose electrons. The atoms that are bonded to the element may affect the oxidation state of the element. The oxidation state of an element depending upon the ability of an element to lose or gain electrons can be positive or negative. The sum of the oxidation state of a molecule will be equal to zero.

Answer to Problem 89A

The oxidation number of nitrogen in ${\text{NaNO}}_{\text{2}}$ is +3

Explanation of Solution

Sodium belongs to group 1 therefore, the common oxidation state of sodium is +1 and that of oxygen is -2. Considering the oxidation state of Nitrogen to be X then

  $\begin{array}{c}+1+(X)+2(-2)=0\\ +1+(X)-4=0\\ +1+X=4\\ X=4-1\\ X=+3\end{array}$

Therefore, the oxidation number of Nitrogen in ${\text{NaNO}}_{\text{2}}$ is $\text{+3}$

b)

Interpretation Introduction

Interpretation: To determine the oxidation state of cobalt in ${\text{CoSO}}_{\text{4}}$

Concept introduction: The oxidation state of any element is the ability of the element to gain or lose electrons. The atoms that are bonded to the element may affect the oxidation state of the element. The oxidation state of an element depending upon the ability of an element to lose or gain electrons can be positive or negative. The sum of the oxidation state of a molecule will be equal to zero.

Answer to Problem 89A

The oxidation state of cobalt in ${\text{CoSO}}_{\text{4}}$ is +2

Explanation of Solution

The common oxidation number of sulfur is +6 and that of oxygen is -2. Consider the oxidation state of $\text{Co}$ to be X, then

  $\begin{array}{c}X+(6)+4(-2)=0\\ X+6-8=0\\ X-2=0\\ X=+2\end{array}$

c)

Interpretation Introduction

Interpretation: To determine the oxidation state of Se in ${\text{SeO}}_{\text{2}}$

Concept Introduction: The oxidation state of any element is the ability of the element to gain or lose electrons. The atoms that are bonded to the element may affect the oxidation state of the element. The oxidation state of an element depending upon the ability of an element to lose or gain electrons can be positive or negative. The sum of the oxidation state of a molecule will be equal to zero.

Answer to Problem 89A

Oxidation state of Se in ${\text{SeO}}_{\text{2}}$ is +4

Explanation of Solution

The common oxidation state of oxygen is -2. Consider the oxidation state of Se to be X then

  $\begin{array}{c}X+2(-2)=0\\ X-4=0\\ X=+4\end{array}$

Therefore, the oxidation state of Selenium is +4

d)

Interpretation Introduction

Interpretation: To determine the oxidation state of Zn in ${\text{Zn(OH)}}_{\text{2}}$

Concept introduction: The oxidation state of any element is the ability of the element to gain or lose electrons. The atoms that are bonded to the element may affect the oxidation state of the element. The oxidation state of an element depending upon the ability of an element to lose or gain electrons can be positive or negative. The sum of the oxidation state of a molecule will be equal to zero.

Answer to Problem 89A

The oxidation state of Zn in ${\text{Zn(OH)}}_{\text{2}}$ is +2

Explanation of Solution

The common oxidation state of hydroxide ion is -1. Consider the oxidation state of Zn to be X then

  $\begin{array}{c}X+2(-1)=0\\ X-2=0\\ X=+2\end{array}$

Therefore, the oxidation number of zinc is +2

e)

Interpretation Introduction

Interpretation: To determine the oxidation state of Pt in ${\text{K}}_{\text{2}}{\text{PtCl}}_{\text{4}}$

Concept introduction: The oxidation state of any element is the ability of the element to gain or lose electrons. The atoms that are bonded to the element may affect the oxidation state of the element. The oxidation state of an element depending upon the ability of an element to lose or gain electrons can be positive or negative. The sum of the oxidation state of a molecule will be equal to zero.

Answer to Problem 89A

Oxidation state of Pt in ${\text{K}}_{\text{2}}{\text{PtCl}}_{\text{4}}$ is +2

Explanation of Solution

The common oxidation state of Chlorine is -1 and the common oxidation state of Potassium is +1. Consider the oxidation state of Pt to be X then

  $\begin{array}{c}2(+1)+X+4(-1)=0\\ 2+X-4=0\\ 2+X=+4\\ X=4-2\\ X=+2\end{array}$