Chapter 19.1, Problem 1PP

(a)

Interpretation Introduction

Interpretation: The given reaction is to be classified as an oxidation or reduction reaction.

Concept introduction:

To classify a change as oxidation and reduction, we should know what is oxidation and reduction.

Oxidation involves:

• Loss of electrons
• Addition of oxygen
• Removal of hydrogen
• Addition of electronegative element
• Removal of an electropositive element
• Increase in oxidation number of the element

Reduction involves:

• A gain of electrons
• Addition of hydrogen
• Removal of oxygen
• Addition of electropositive element
• Removal of electronegative element
• A decrease in oxidation number of the element

Answer to Problem 1PP

The given change is reduction.

Explanation of Solution

The given reaction is:

${\text{I}}_2+2{\text{e}}^{-}\to 2{\text{I}}^{-}$

The reaction involves the gain of electrons. So it is a reduction.

(b)

Interpretation Introduction

Interpretation: The given reaction is to be classified as an oxidation or reduction reaction.

Concept introduction:

To classify a change as oxidation and reduction, we should know what is oxidation and reduction.

Oxidation involves:

• Loss of electrons
• Addition of oxygen
• Removal of hydrogen
• Addition of electronegative element
• Removal of an electropositive element
• Increase in oxidation number of the element

Reduction involves:

• A gain of electrons
• Addition of hydrogen
• Removal of oxygen
• Addition of electropositive element
• Removal of electronegative element
• A decrease in oxidation number of the element

Answer to Problem 1PP

The given change is oxidation.

Explanation of Solution

The given reaction is:

$\text{K}\to {\text{K}}^{+}+{\text{e}}^{-}$

The reaction involves a loss of electrons. So, it is oxidation.

(c)

Interpretation Introduction

Interpretation: The given reaction is to be classified as an oxidation or reduction reaction.

Concept introduction:

To classify a change as oxidation and reduction, we should know what is oxidation and reduction.

Oxidation involves:

• Loss of electrons
• Addition of oxygen
• Removal of hydrogen
• Addition of electronegative element
• Removal of an electropositive element
• Increase in oxidation number of the element

Reduction involves:

• A gain of electrons
• Addition of hydrogen
• Removal of oxygen
• Addition of electropositive element
• Removal of electronegative element
• A decrease in oxidation number of the element

Answer to Problem 1PP

The given change is oxidation.

Explanation of Solution

The given reaction is:

$\text{F}{\text{e}}^{+2}\to \text{F}{\text{e}}^{+3}+{\text{e}}^{-}$

The reaction involves a loss of electrons. So, it is oxidation.

(d)

Interpretation Introduction

Interpretation: The given reaction is to be classified as an oxidation or reduction reaction.

Concept introduction:

To classify a change as oxidation and reduction, we should know what is oxidation and reduction.

Oxidation involves:

• Loss of electrons
• Addition of oxygen
• Removal of hydrogen
• Addition of electronegative element
• Removal of an electropositive element
• Increase in oxidation number of the element

Reduction involves:

• A gain of electrons
• Addition of hydrogen
• Removal of oxygen
• Addition of electropositive element
• Removal of electronegative element
• A decrease in oxidation number of the element

Answer to Problem 1PP

The given change is reduction.

Explanation of Solution

The given reaction is:

$\text{A}{\text{g}}^{+}+{\text{e}}^{-}\to \text{A}\text{g}$

The reaction involves the gain of electrons. So it is a reduction.