Chapter 19, Problem 74A

Interpretation Introduction

(a)

Interpretation:

The given reaction is to be classified as 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 electropositive element
• Increase in oxidation number of the element

Reduction involves:

• Gain of electrons.
• Addition of hydrogen
• Removal of oxygen
• Addition of electropositive element
• Removal of electronegative element
• Decrease in oxidation number of the element

Answer to Problem 74A

The given change is oxidation.

Explanation of Solution

The given reaction is:

$2C{l}^{-}\to C{l}_2+2e^{-}$

The reaction involves loss of electron. So it is oxidation.

Interpretation Introduction

(b)

Interpretation:

The given reaction is to be classified as 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 electropositive element
• Increase in oxidation number of the element

Reduction involves:

• Gain of electrons.
• Addition of hydrogen
• Removal of oxygen
• Addition of electropositive element
• Removal of electronegative element
• Decrease in oxidation number of the element

Answer to Problem 74A

The given change is oxidation.

Explanation of Solution

The given reaction is:

$Na\to N{a}^{+}+e^{-}$

The reaction involves loss of electron. So it is oxidation.

Interpretation Introduction

(c)

Interpretation:

The given reaction is to be classified as 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 electropositive element
• Increase in oxidation number of the element

Reduction involves:

• Gain of electrons.
• Addition of hydrogen
• Removal of oxygen
• Addition of electropositive element
• Removal of electronegative element
• Decrease in oxidation number of the element

Answer to Problem 74A

The given change is reduction.

Explanation of Solution

The given reaction is:

$C{a}^{+2}+2e^{-}\to 2Ca$

The reaction involves gain of electron. So it is reduction.

Interpretation Introduction

(d)

Interpretation:

The given reaction is to be classified as 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 electropositive element
• Increase in oxidation number of the element

Reduction involves:

• Gain of electrons.
• Addition of hydrogen
• Removal of oxygen
• Addition of electropositive element
• Removal of electronegative element
• Decrease in oxidation number of the element

Answer to Problem 74A

The given change is reduction.

Explanation of Solution

The given reaction is:

$O_2+4e^{-}\to 2O^{2-}$

The reaction involves gain of electron. So it is reduction.