Chapter 20, Problem 61A

(a)

Interpretation Introduction

Interpretation: The oxidation number of element X on each side of the equation is to be identified.

Concept Introduction: Redox reactions include the transfer of electrons between two reactants. The redox reactions include combination reactions, combustion reactions, decomposition reactions, and single-replacement reactions.

Answer to Problem 61A

The oxidation number of the element $\text{X}$ is $\text{0}$ on the left side and $\text{+3}$ on the right side.

Explanation of Solution

Consider the given redox equation:

  $2\text{X}+3{\text{H}}_{\text{2}}\text{Y} \to {\text{X}}_{\text{2}}{\text{Y}}_{\text{3}}{\text{+3H}}_{\text{2}}$

  $\text{X}$ on the left side has the oxidation number of $0$ since it is in elemental form.

  $\text{X}$ on the right side has the oxidation number of $+3$ since $\text{X}$ is a neutral compound with $\text{Y}$ while $\text{Y}$ will be in $-2$ oxidation number.

The chemical equation along with $\text{X}$

charge is given as follows:

  $2\stackrel{0}{\text{X}}+3{\text{H}}_{\text{2}}\text{Y} \to \stackrel{+3}{{\text{X}}_2}{\text{Y}}_{\text{3}}{\text{+3H}}_{\text{2}}$

(b)

Interpretation Introduction

Interpretation: The oxidation number of element Y on each side of the equation is to be identified.

Concept Introduction: Redox reactions include the transfer of electrons between two reactants. The redox reactions include combination reactions, combustion reactions, decomposition reactions, and single-replacement reactions.

Answer to Problem 61A

The oxidation number of the element $\text{Y}$ is $-2$ on both the sides of the equation.

Explanation of Solution

Consider the given redox equation:

  $2\text{X}+3{\text{H}}_{\text{2}}\text{Y} \to {\text{X}}_{\text{2}}{\text{Y}}_{\text{3}}{\text{+3H}}_{\text{2}}$

Since $\text{H}$ has an oxidation number of $+1$ , $\text{Y}$ will have an oxidation number of $-2$ .

  $\text{X}$ on the right side has the oxidation number of $+3$ since $\text{X}$ is a neutral compound with $\text{Y}$ while $\text{Y}$ will be in $-2$ oxidation number.

So, on both sides the oxidation number of $\text{Y}$ will be $-2$ .

The chemical equation along with $\text{Y}$

charge is given as follows:

  $2\text{X}+3{\text{H}}_{\text{2}}\stackrel{-2}{\text{Y} }\to {\text{X}}_2\stackrel{-2}{{\text{Y}}_{\text{3}}}{\text{+3H}}_{\text{2}}$

(c)

Interpretation Introduction

Interpretation: The element that is oxidized in this equation is to be identified.

Concept Introduction: Redox reactions include the transfer of electrons between two reactants. The redox reactions include combination reactions, combustion reactions, decomposition reactions, and single-replacement reactions.

Answer to Problem 61A

The element that is oxidized in this equation is $\text{X}$ .

Explanation of Solution

Consider the given redox equation:

  $2\text{X}+3{\text{H}}_{\text{2}}\text{Y} \to {\text{X}}_{\text{2}}{\text{Y}}_{\text{3}}{\text{+3H}}_{\text{2}}$

The above equation with its charge is given as follows:

  $2\stackrel{0}{\text{X}}+3\stackrel{+1}{{\text{H}}_{\text{2}}}\stackrel{-2}{\text{Y} }\to \stackrel{+3}{{\text{X}}_2}\stackrel{-2}{{\text{Y}}_{\text{3}}}\text{+3}\stackrel{0}{{\text{H}}_{\text{2}}}$

The oxidation number of $\text{X}$ is changed from $\text{0}$ to $\text{+3}$ .

So, there is increase in oxidation number of $\text{X}$ , thus it is oxidized.

(d)

Interpretation Introduction

Interpretation: The element that is reduced in this equation is to be identified.

Concept Introduction: Redox reactions include the transfer of electrons between two reactants. The redox reactions include combination reactions, combustion reactions, decomposition reactions, and single-replacement reactions.

Answer to Problem 61A

The element that is reduced in this equation is $\text{Y}$ .

Explanation of Solution

Consider the given redox equation:

  $2\text{X}+3{\text{H}}_{\text{2}}\text{Y} \to {\text{X}}_{\text{2}}{\text{Y}}_{\text{3}}{\text{+3H}}_{\text{2}}$

The above equation with its charge is given as follows:

  $2\stackrel{0}{\text{X}}+3\stackrel{+1}{{\text{H}}_{\text{2}}}\stackrel{-2}{\text{Y} }\to \stackrel{+3}{{\text{X}}_2}\stackrel{-2}{{\text{Y}}_{\text{3}}}\text{+3}\stackrel{0}{{\text{H}}_{\text{2}}}$

The oxidation number of $\text{H}$ is changed from $+1$ to $0$ .

So, there is decrease in oxidation number of $\text{H}$ , thus it is reduced.