Chapter 14, Problem 3E

Interpretation Introduction

Interpretation:

Some common processes that involve redox reactions are to be listed.

Concept Introduction:

Oxidation is the addition of an electronegative element or the removal of an electropositive element in the chemical reaction.

Reduction is the addition of an electropositive element or the removal of an electronegative element in the chemical reaction.

The chemical reaction in which oxidation and reduction takes place simultaneously is called a redox reaction.

An oxidizing agent is a substance that has the capacity to oxidize the other substances and get reduced in a chemical reaction.

A reducing agent is a substance that has the capacity to reduce the other substances and get oxidized in a chemical reaction.

Answer to Problem 3E

Solution:

Some common examples that involve redox reactions are:

Burning of coal,

Respiration,

Photosynthesis and

Rusting of iron

Explanation of Solution

The chemical equation for the respiration reaction is as follows:

${\text{C}}_6{\text{H}}_{12}{\text{O}}_6+6{\text{O}}_2\to 6{\text{CO}}_2+6{\text{H}}_2\text{O}$

An oxidizing agent gains electrons easily and a reducing agent loses electrons easily in a chemical reaction.

$\underset{0}{{\text{C}}_6}\underset{+1}{{\text{H}}_{12}}\underset{-2}{{\text{O}}_6}+6\underset{0}{{\text{O}}_2}\to 6\underset{+4}{\text{C}}\underset{-2}{{\text{O}}_2}+6\underset{+1}{{\text{H}}_2}\underset{-2}{\text{O}}$

In this chemical reaction, the oxidation state of ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6$ increases from $0$ to $+4$ and loss of the electrons occurs. Therefore, ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6$ is oxidized in this reaction.

In this chemical reaction, the oxidation state of ${\text{O}}_2$ reduces from $0$ to $-2$ and the gain of electrons occurs. Therefore, ${\text{O}}_2$ is reduced in this reaction.

The chemical equation for the photosynthesis reaction is as follows:

${\text{6CO}}_2+6{\text{H}}_2\text{O}\to {\text{C}}_6{\text{H}}_{12}{\text{O}}_6+6{\text{O}}_2$

An oxidizing agent gains electrons easily and a reducing agent loses electrons easily in a chemical reaction.

$\text{6}\underset{+4}{\text{C}}\underset{-2}{{\text{O}}_2}+6\underset{+1}{{\text{H}}_2}\underset{-2}{\text{O}}\to \underset{0}{{\text{C}}_6}\underset{+1}{{\text{H}}_{12}}\underset{-2}{{\text{O}}_6}+6\underset{0}{{\text{O}}_2}$

In this chemical reaction, the oxidation state of ${\text{H}}_2\text{O}$ increases from $-2$ to $0$ and the loss of electrons occurs. Therefore, ${\text{H}}_2\text{O}$ is oxidized in this reaction.

In this chemical reaction, the oxidation state of ${\text{CO}}_2$ reduces from $+4$ to $0$ and the gain of the electrons occurs. Therefore, ${\text{CO}}_2$ is reduced in this reaction.

The chemical equation for the burning of coal is as follows:

$\text{C}\text{+}{\text{O}}_2\to {\text{CO}}_2$

An oxidizing agent gains electrons easily and a reducing agent loses electrons easily in a chemical reaction.

$\underset{0}{\text{C}}\text{+}\underset{0}{{\text{O}}_2}\to \underset{+4}{\text{C}}\underset{-2}{{\text{O}}_2}$

In this chemical reaction, the oxidation state of $\text{C}$ increases from $0$ to $+4$ and the gain of oxygen occurs. Therefore, $\text{C}$ is oxidize.

In this chemical reaction, the oxidation state of ${\text{O}}_2$ reduces from $0$ to $-2$ and the gain of electrons occurs. Therefore, ${\text{O}}_2$ is reduced in this reaction.

The chemical equation for the rusting of iron is as follows:

$\text{4Fe}+3{\text{O}}_2\to 2{\text{Fe}}_2{\text{O}}_3$

Oxidation is the loss of electrons or gain of oxygen in a chemical reaction. Reduction is the gain of electrons or loss of oxygen in the chemical reaction.

$\text{4}\underset{0}{\text{Fe}}+3\underset{0}{{\text{O}}_2}\to 2\underset{+3}{{\text{Fe}}_2}\underset{-2}{{\text{O}}_3}$

In this chemical reaction, the oxidation state of $\text{Fe}$ increases from 0 to $+3$ and the gain of oxygen occurs. Therefore, $\text{Fe}$ is oxidized in this reaction.

In this chemical reaction, the oxidation state of ${\text{O}}_2$ is reduced from 0 to $-2$ and the gain of electrons occurs. Therefore, ${\text{O}}_2$ is reduced in this reaction.

Conclusion

Some common processes which involve redox reactions are rusting of iron and photosynthesis reaction.