Chapter 18.1, Problem 5RQ

(a)

Interpretation Introduction

Interpretation: From the given reaction, the element that is oxidized and reduced needs to be determined.

$\text{4Fe}\left(s\right)+3{\text{O}}_{\text{2}}\left(g\right)\to 2{\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}\left(s\right)$

Concept introduction: A chemical reaction which involves transfer of electron is redox or oxidation-reduction reaction. Oxidation state is the charge assigned to an atom in a compound. Oxidation-reduction reaction involves gain and loss of electrons from atoms.

Answer to Problem 5RQ

Iron is oxidized and oxygen is reduced.

Explanation of Solution

Given reaction is as follows:

$\text{4Fe}\left(s\right)+3{\text{O}}_{\text{2}}\left(g\right)\to 2{\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}\left(s\right)$

In this reaction, oxidation state of Fe increases from 0 to +3 and oxidation state of oxygen decreases form 0 to -2. Thus, iron is oxidized and oxygen is reduced.

(b)

Interpretation Introduction

Interpretation: From the given reaction, the element that is oxidized and reduced needs to be determined.

$\text{Zn}\left(s\right)+2{\text{AgNO}}_{\text{3}}\left(aq\right)\to \text{Zn}{\left({\text{NO}}_{\text{3}}\right)}_2\left(aq\right)+2\text{Ag}\left(s\right)$

Concept introduction: A chemical reaction which involves transfer of electron is redox or oxidation-reduction reaction. Oxidation state is the charge assigned to an atom in a compound. Oxidation-reduction reaction involves gain and loss of electrons from atoms.

Answer to Problem 5RQ

Zinc is oxidized and silver is reduced.

Explanation of Solution

Given reaction is as follows:

$\text{Zn}\left(s\right)+2{\text{AgNO}}_{\text{3}}\left(aq\right)\to \text{Zn}{\left({\text{NO}}_{\text{3}}\right)}_2\left(aq\right)+2\text{Ag}\left(s\right)$

In this reaction, oxidation state of Zn increases from 0 to +2 and oxidation state of Ag decreases form +1 to 0. Thus, Zn is oxidized and Ag is reduced.

(c)

Interpretation Introduction

Interpretation: From given reaction, the element that is oxidized and reduced needs to be determined.

$2\text{K}\left(s\right)+{\text{Cl}}_{\text{2}}\left(g\right)\to 2\text{KCl}\left(s\right)$

Concept introduction: A chemical reaction which involves transfer of electron is redox or oxidation-reduction reaction. Oxidation state is the charge assigned to an atom in a compound. Oxidation-reduction reaction involves gain and loss of electrons from atoms.

Answer to Problem 5RQ

Potassium is oxidized and chlorine is reduced.

Explanation of Solution

Given reaction is as follows:

$2\text{K}\left(s\right)+{\text{Cl}}_{\text{2}}\left(g\right)\to 2\text{KCl}\left(s\right)$

In this reaction, oxidation state of potassium increases from 0 to +1 and oxidation state of chlorine decreases form 0 to -1. Thus potassium is oxidized and chlorine is reduced.

(d)

Interpretation Introduction

Interpretation: From given reaction, the element that is oxidized and reduced needs to be determined.

$\text{2Ca}\left(s\right)+{\text{O}}_{\text{2}}\left(g\right)\to 2\text{CaO}\left(s\right)$

Concept introduction: A chemical reaction which involves transfer of electron is redox or oxidation-reduction reaction. Oxidation state is the charge assigned to an atom in a compound. Oxidation-reduction reaction involves gain and loss of electrons from atoms.

Answer to Problem 5RQ

Calcium is oxidized and oxygen is reduced.

Explanation of Solution

Given reaction is as follows:

$\text{2Ca}\left(s\right)+{\text{O}}_{\text{2}}\left(g\right)\to 2\text{CaO}\left(s\right)$

In this reaction, oxidation state of Ca increases from 0 to +2 and oxidation state of oxygen decreases form 0 to -2. Thus, calcium is oxidized and oxygen is reduced.