Chapter 3, Problem 122E

(a)

Interpretation Introduction

Interpretation: The naming of the compounds is to be checked. Correct naming of the compound is to be stated.

Concept introduction: While naming covalent compound, the name of the cation is written first, followed by the name of the anion. Generally, the cation present is a metal or a polyatomic cation, whereas the anion is a non-metal.

Explanation of Solution

To determine: The error in the naming of ${\text{FeCl}}_{\text{3}}$

${\text{FeCl}}_{\text{3}}$ is a binary compound. Roman numerals are used to show the oxidation state of compounds that exhibit more than one oxidation state. Iron $\left(\text{Fe}\right)$ is transition metal and exhibits more than one oxidation state.

Hence, the given name iron chloride of ${\text{FeCl}}_{\text{3}}$ is wrong because oxidation state is not given.

To determine: The correct naming of ${\text{FeCl}}_{\text{3}}$.

Iron $\left(\text{Fe}\right)$ exhibits $+2\text{and}+3$ oxidation state. Hence, Roman numeral is used to show the oxidation state of this compound.

Here iron $\left({\text{Fe}}^{3+}\right)$ ion is cation and chlorine $\left({\text{Cl}}^{-}\right)$ ion is mono-atomic anion. The oxidation state of iron is $+3$ because total charge on anion is $-3$. Since compound should be electrically neutral, the name of ${\text{FeCl}}_{\text{3}}$ compound is iron (III) chloride.

Conclusion

The Roman numerals are used in the naming of compounds that exhibit more than one oxidation state. Iron is such compound that exhibit more than one oxidation state. So, the correct name of the compound is iron (III) chloride.

(b)

Interpretation Introduction

Interpretation: The naming of the compounds is to be checked. Correct naming of the compound is to be stated.

Concept introduction: While naming covalent compound, the name of the cation is written first, followed by the name of the anion. Generally, the cation present is a metal or a polyatomic cation, whereas the anion is a non-metal.

Explanation of Solution

To determine: The error in the naming of ${\text{NO}}_2$

The element nitrogen $\left(\text{N}\right)$ is not a transition metal. It exhibits only one oxidation state. The Roman numerals are used only in the naming of compounds that exhibit more than one oxidation state

Hence, the given name nitrogen (IV) oxide of ${\text{NO}}_2$ is wrong.

To determine: The correct naming of ${\text{NO}}_2$.

In naming of covalent compound, the name of cation comes first which is the name of element. Anion is named second which is also the name of element. The anions are named with the ending -ide. Also the number of respective atoms present is denoted by using prefixes like mono, di tri.

Hence, the name of given compound is nitrogen dioxide.

Conclusion

The Roman numerals are used only in the naming of transition metals compounds. Nitrogen is not a transition metal. So, the correct name of the compound is nitrogen dioxide.

(c)

Interpretation Introduction

Interpretation: The naming of the compounds is to be checked. Correct naming of the compound is to be stated.

Concept introduction: While naming covalent compound, the name of the cation is written first, followed by the name of the anion. Generally, the cation present is a metal or a polyatomic cation, whereas the anion is a non-metal.

Explanation of Solution

To determine: The error in the naming of $\text{CaO}$

The element calcium $\left(\text{Ca}\right)$ is not a transition metal. It is an alkaline earth metal. The Roman numerals are used only in the naming of compounds that exhibit more than one oxidation state

Hence, the given name calcium (II) monoxide of $\text{CaO}$ is wrong.

To determine: The correct naming of $\text{CaO}$.

In naming of covalent compound, the name of cation comes first which is the name of element. Anion is named second which is also the name of element. The anions are named with the ending -ide.

In $\text{CaO}$ compound, cation is calcium $\left({\text{Ca}}^{\text{2+}}\right)$ and anion is oxygen $\left({\text{O}}^{2-}\right)$.

Hence, the name of given compound is calcium oxide.

Conclusion

The Roman numerals are used only in the naming of transition metals compounds. Calcium is not a transition metal. So, the correct name of the compound is calcium oxide.

(d)

Interpretation Introduction

Interpretation: The naming of the compounds is to be checked. Correct naming of the compound is to be stated.

Concept introduction: While naming covalent compound, the name of the cation is written first, followed by the name of the anion. Generally, the cation present is a metal or a polyatomic cation, whereas the anion is a non-metal.

Explanation of Solution

To determine: The error in the naming of ${\text{Al}}_2{\text{S}}_3$.

The element Alumunium $\left(\text{Al}\right)$ is a metal that exhibit only one oxidation state. Prefix is used when two non-metals are combined and contains more than one atom.

Hence, the given name dialuminum trisulfide of ${\text{Al}}_2{\text{S}}_3$ is wrong.

To determine: The correct naming of ${\text{Al}}_2{\text{S}}_3$.

In naming of covalent compound, the name of cation comes first which is the name of element. Anion is named second which is also the name of element. The anions are named with the ending -ide.

In ${\text{Al}}_2{\text{S}}_3$ compound, cation is alumunium $\left({\text{Al}}^{\text{3+}}\right)$ and anion is sulfur $\left({\text{S}}^{2-}\right)$. Since compound should be electrically neutral, two aluminum cation combines with three sulfur anion to balance the charge.

Hence, the name of given compound is alumunium sulfide.

Conclusion

Prefix is mostly used when two non-metals are combined and contains more than one atom. Aluminum is a metal and sulfur is non-metal. Hence, the correct name of ${\text{Al}}_2{\text{S}}_3$ is alumunium sulfide.

(e)

Interpretation Introduction

Interpretation: The naming of the compounds is to be checked. Correct naming of the compound is to be stated.

Concept introduction: While naming covalent compound, the name of the cation is written first, followed by the name of the anion. Generally, the cation present is a metal or a polyatomic cation, whereas the anion is a non-metal.

Explanation of Solution

To determine: The error in the naming of $\text{Mg}{\left({\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}\right)}_{\text{2}}$

The symbol $\text{Mg}$ represents magnesium. It is an alkaline earth metal.

Hence, the given name manganese diacetate of $\text{Mg}{\left({\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}\right)}_{\text{2}}$ is wrong.

To determine: The correct naming of $\text{Mg}{\left({\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}\right)}_{\text{2}}$.

In naming of covalent compound, the name of cation comes first which is the name of element. Anion is named second which is also the name of element. The poly atomic anions are named with the ending -ate.

In $\text{Mg}{\left({\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}\right)}_{\text{2}}$ compound, cation is magnesium $\left({\text{Mg}}^{\text{2+}}\right)$ and anion is acetate $\left({\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}{}^{2-}\right)$.

Hence, the name of given compound is magnesium acetate.

Conclusion

Prefix is mostly used when two non-metals are combined and contains more than one atom. Magnesium is a metal. Hence, the correct name of $\text{Mg}{\left({\text{C}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}\right)}_{\text{2}}$ is magnesium acetate.

(f)

Interpretation Introduction

Interpretation: The naming of the compounds is to be checked. Correct naming of the compound is to be stated.

Concept introduction: While naming covalent compound, the name of the cation is written first, followed by the name of the anion. Generally, the cation present is a metal or a polyatomic cation, whereas the anion is a non-metal.

Explanation of Solution

To determine: The error in the naming of ${\text{FePO}}_4$

Roman numerals are used to show the oxidation state of compounds that exhibit more than one oxidation state. Iron $\left(\text{Fe}\right)$ is transition metal and exhibits more than one oxidation state. The given charge on iron is $+2$ but the polyatomic phosphate ion $\left({\text{PO}}_{\text{4}}{}^{3-}\right)$ contains $-3$ charge. So, the compound is not neutral.

Hence, the given name iron (II) phosphate of ${\text{FePO}}_4$ is wrong.

To determine: The correct naming of ${\text{FePO}}_4$.

Iron $\left(\text{Fe}\right)$ exhibits $+2\text{and}+3$ oxidation state. Hence, Roman numeral is used to show the oxidation state of this compound.

Here iron $\left({\text{Fe}}^{3+}\right)$ ion is cation and phosphate ion $\left({\text{PO}}_{\text{4}}{}^{3-}\right)$ is anion. The oxidation state of iron is $+3$ because total charge on anion is $-3$. Since compound should be electrically neutral, the name of ${\text{FePO}}_4$ compound is iron (III) phosphate.

Conclusion

The Roman numerals are used in the naming of compounds that exhibit more than one oxidation state. Iron is such compound that exhibit more than one oxidation state. So, the correct name of the compound is iron (III) phosphate.

(g)

Interpretation Introduction

Interpretation: The naming of the compounds is to be checked. Correct naming of the compound is to be stated.

Concept introduction: While naming covalent compound, the name of the cation is written first, followed by the name of the anion. Generally, the cation present is a metal or a polyatomic cation, whereas the anion is a non-metal.

Explanation of Solution

To determine: The error in the naming of ${\text{P}}_2{\text{S}}_5$

The element phosphorous $\left(\text{P}\right)$ is a non-metal. Prefix is used when two non-metals are combined and contains more than one atom.

Hence, the given name phosphorus sulfide of ${\text{P}}_2{\text{S}}_5$ is wrong.

To determine: The correct naming of ${\text{P}}_2{\text{S}}_5$.

In naming of covalent compound, the name of cation comes first which is the name of element. Anion is named second which is also the name of element. The anions are named with the ending -ide. Prefix is used when two non-metals are combined and contains more than one atom.

Phosphorous $\left(\text{P}\right)$ and sulfur $\left(\text{S}\right)$ are nonmetals.

Hence, the name of given compound is diphosphorous pentasulfide.

Conclusion

Prefix is mostly used when two non-metals are combined and contains more than one atom. Hence, the correct name of ${\text{P}}_2{\text{S}}_5$ is diphosphorous pentasulfide.

(h)

Interpretation Introduction

Interpretation: The naming of the compounds is to be checked. Correct naming of the compound is to be stated.

Concept introduction: While naming covalent compound, the name of the cation is written first, followed by the name of the anion. Generally, the cation present is a metal or a polyatomic cation, whereas the anion is a non-metal.

Explanation of Solution

To determine: The error in the naming of ${\text{Na}}_2{\text{O}}_2$

The oxidation state of sodium $\left({\text{Na}}^{\text{+}}\right)$ is $+1$.

Oxygen $\left({\text{O}}^{2-}\right)$ is an anion having oxidation state $-2$. So, the compound formed is not neutral.

Sodium peroxide is formed when two sodium and oxygen atoms is combined together.

Hence, the given name sodium oxide of ${\text{Na}}_2{\text{O}}_2$ is wrong.

To determine: The correct naming of ${\text{Na}}_2{\text{O}}_2$.

Sodium peroxide is formed when two sodium $\left({\text{Na}}^{\text{+}}\right)$ ion and single peroxide $\left({\text{O}}^{2-}\right)$ ion is combined together. So, the compound formed is neutral.

Hence, the name of given compound is sodium peroxide.

Conclusion

The compound is always electrically neutral. The value of cation and anion should be balanced during formation of any compound.

(i)

Interpretation Introduction

Interpretation: The naming of the compounds is to be checked. Correct naming of the compound is to be stated.

Concept introduction: While naming covalent compound, the name of the cation is written first, followed by the name of the anion. Generally, the cation present is a metal or a polyatomic cation, whereas the anion is a non-metal.

Explanation of Solution

To determine: The error in the naming of ${\text{HNO}}_3$

In the acidic compound ${\text{HNO}}_3$ the cation is hydrogen $\left({\text{H}}^{\text{+}}\right)$ and anion is nitrate $\left({\text{NO}}_3{}^{-}\right)$

• If the name of anions ends in “ate-” then acid name ends in –ic or –ric

Hence, the given name nitrate acid of ${\text{HNO}}_3$ is wrong.

To determine: The correct naming of ${\text{HNO}}_3$.

In the acidic compound ${\text{HNO}}_3$ the cation is hydrogen $\left({\text{H}}^{\text{+}}\right)$ and anion is nitrate $\left({\text{NO}}_3{}^{-}\right)$

• If the name of anions ends in “ate-” then acid name ends in –ic or –ric

Hence, the given name is nitric acid.

Conclusion

In naming of acidic compound roots of anion is considered.

(j)

Interpretation Introduction

Interpretation: The naming of the compounds is to be checked. Correct naming of the compound is to be stated.

Concept introduction: While naming covalent compound, the name of the cation is written first, followed by the name of the anion. Generally, the cation present is a metal or a polyatomic cation, whereas the anion is a non-metal.

Explanation of Solution

To determine: The error in the naming of ${\text{H}}_2\text{S}$.

In the acidic compound ${\text{H}}_2\text{S}$ the cation is hydrogen $\left({\text{H}}^{\text{+}}\right)$ and anion is sulfur $\left({\text{S}}^{2-}\right)$

• When oxygen is not present in anion, then acids is named by using “hydro-” in prefix.

Hence, the given name nitrate acid of ${\text{H}}_2\text{S}$ is wrong.

To determine: The correct naming of ${\text{H}}_2\text{S}$.

In the acidic compound ${\text{H}}_2\text{S}$ the cation is hydrogen $\left({\text{H}}^{\text{+}}\right)$ and anion is sulfur $\left({\text{S}}^{2-}\right)$

• When oxygen is not present in anion, then acids is named by using “hydro-” in prefix.

Hence, the given name is hydro sulfuric acid.

Conclusion

If oxygen is not present in anion, then acids is named by using “hydro-” in prefix.