Chapter 20.2, Problem 11SP

(a)

Interpretation Introduction

Interpretation: The oxidation number of chlorine, $\text{Cl}$ in ${\text{KClO}}_{\text{3}}$ is to be calculated.

Concept Introduction: The zero, positive or negative numbers that are assigned to an atom for indicating its degree of oxidation and reduction is the oxidation number. This number indicates the number of electrons that are either gained or lost during the bond formation in a chemical compound.

Answer to Problem 11SP

The oxidation number of $\text{Cl}$ in ${\text{KClO}}_{\text{3}}$ is $\text{+5}$ .

Explanation of Solution

Certain rules must be followed to get the oxidation number of elements in a chemical compound. They are:

• The oxidation number of oxygen is $-\text{2}$ .
• For a neutral compound, the total sum of the oxidation number is zero.
• For ionic compounds with a charge, the total sum of oxidation number is equal to its charge.
• The elements present in the alkaline metal or group one have an oxidation number of +1 in common.
• The elements present in the alkaline earth metals have an oxidation number of $\text{+2}$ .

The given compound, ${\text{KClO}}_{\text{3}}$ is a neutral compound with a group 1 element, potassium attached to it. So the oxidation number of chlorine can be calculated as,

Let $x$ be the oxidation number of $\text{Cl}$ ,

  $\begin{array}{c}x+1+3\times \left(-2\right)=0\\ x+1-6=0\\ x=6-1\\ x=5\end{array}$

So, the oxidation number of chlorine is $\text{+5}$ .

(b)

Interpretation Introduction

Interpretation: The oxidation number of chlorine, $\text{Cl}$ in $\text{Ca}{\left({\text{ClO}}_4\right)}_2$ is to be calculated.

Concept Introduction: The zero, positive or negative numbers that are assigned to an atom for indicating its degree of oxidation and reduction is the oxidation number. This number indicates the number of electrons that are either gained or lost during the bond formation in a chemical compound.

Answer to Problem 11SP

The oxidation number of $\text{Cl}$ in $\text{Ca}{\left({\text{ClO}}_4\right)}_2$ is $\text{+7}$ .

Explanation of Solution

Certain rules must be followed to get the oxidation number of elements in a chemical compound. They are:

• The oxidation number of oxygen is $-\text{2}$ .
• For a neutral compound, the total sum of the oxidation number is zero.
• For ionic compounds with a charge, the total sum of oxidation number is equal to its charge.
• The elements present in the alkaline metal or group one have an oxidation number of +1 in common.
• The elements present in the alkaline earth metals have an oxidation number of $\text{+2}$ .

The given compound, $\text{Ca}{\left({\text{ClO}}_4\right)}_2$ is neutral and also calcium is an element from group 2. So its oxidation number is +2. The oxidation number of $\text{Cl}$ in $\text{Ca}{\left({\text{ClO}}_4\right)}_2$ can be calculated as,

Let $x$ be the oxidation number of $\text{Cl}$ .

  $\begin{array}{c}2x+2+8\times \left(-2\right)=0\\ 2x+2-16=0\\ 2x=16-2\\ x=7\end{array}$

So, the oxidation number of $\text{Cl}$ is $\text{+7}$ .

(c)

Interpretation Introduction

Interpretation: The oxidation number of chlorine, $\text{Cl}$ in ${\text{Cl}}_2$ is to be calculated.

Concept Introduction: The zero, positive or negative numbers that are assigned to an atom for indicating its degree of oxidation and reduction is the oxidation number. This number indicates the number of electrons that are either gained or lost during the bond formation in a chemical compound.

Answer to Problem 11SP

The oxidation number of $\text{Cl}$ in ${\text{Cl}}_2$ is $0$ .

Explanation of Solution

Certain rules must be followed to get the oxidation number of elements in a chemical compound. They are:

• The oxidation number of oxygen is $-\text{2}$ .
• For a neutral compound, the total sum of the oxidation number is zero.
• For ionic compounds with a charge, the total sum of oxidation number is equal to its charge.
• The elements present in the alkaline metal or group one have an oxidation number of +1 in common.
• The elements present in the alkaline earth metals have an oxidation number of $\text{+2}$ .

Chlorine, $\text{Cl}$ in ${\text{Cl}}_2$ is in its elemental form. Any chemical species that are present in the elemental form is found to have an oxidation number of zero. So, the oxidation number of $\text{Cl}$ in ${\text{Cl}}_2$ is zero.

(d)

Interpretation Introduction

Interpretation: The oxidation number of chlorine, $\text{Cl}$ in ${\text{Cl}}_2\text{O}$ is to be calculated.

Concept Introduction: The zero, positive or negative numbers that are assigned to an atom for indicating its degree of oxidation and reduction is the oxidation number. This number indicates the number of electrons that are either gained or lost during the bond formation in a chemical compound.

Answer to Problem 11SP

The oxidation number of $\text{Cl}$ in ${\text{Cl}}_2\text{O}$ is $+2$ .

Explanation of Solution

Certain rules must be followed to get the oxidation number of elements in a chemical compound. They are,

• The oxidation number of oxygen is $-\text{2}$ .
• For a neutral compound, the total sum of the oxidation number is zero.
• For ionic compounds with a charge, the total sum of oxidation number is equal to its charge.
• The elements present in the alkaline metal or group one have an oxidation number of +1 in common.
• The elements present in the alkaline earth metals have an oxidation number of $\text{+2}$ .

The given compound ${\text{Cl}}_2\text{O}$ is neutral. The oxidation number of $\text{Cl}$ in ${\text{Cl}}_2\text{O}$ can be calculated as,

Let $x$ be the oxidation number of $\text{Cl}$ .

  $\begin{array}{c}x+1\times \left(-2\right)=0\\ x-2=0\\ x=2\end{array}$

So, the oxidation number of $\text{Cl}$ in ${\text{Cl}}_2\text{O}$ is $+2$ .