Chapter 4, Problem 8A

(a)

Interpretation Introduction

Interpretation: Correct nomenclature of ${\text{PbI}}_4$ with appropriate roman numerals must be provided.

Concept introduction: An ionic compound that contains only two elements, one present as a cation and one as an anion, is called a binary ionic compound. These compounds are of three types:

• Type I binary ionic compound: which contain ions of metals that can show only one type of oxidation state.
• Type II binary ionic compound: which contain ions of metals that can show more than one type of oxidation state.
• Type III binary ionic compound: contains ions that are generated from non metals.

Answer to Problem 8A

Correct nomenclature of ${\text{PbI}}_4$ is Lead(IV) iodide.

Explanation of Solution

Rules set for constituting nomenclature of binary ionic compounds are as follows:

• Position of both cation and anion forming element has to be identified for idea of their oxidation state.
• Always the cationic species name is retained and placed first in nomenclature.
• After the cation name, anion name is placed with suffix ‘-ide’ at the end of its root name.
• The oxidation state is expressed as roman numeral after cation name, enclosed in bracket.

In ${\text{PbI}}_4$ the metal Pb is in $+4$ oxidation state so IV is used in brackets after the metal name. ${\text{I}}^{-}$ is named as iodide. So Lead(IV) iodide is the correct nomenclature.

(b)

Interpretation Introduction

Interpretation: Correct nomenclature of ${\text{TiO}}_2$ with appropriate roman numerals must be provided.

Concept introduction: An ionic compound that contains only two elements, one present as a cation and one as an anion, is called a binary ionic compound. These compounds are of three types:

• Type I binary ionic compound: which contain ions of metals that can show only one type of oxidation state.
• Type II binary ionic compound: which contain ions of metals that can show more than one type of oxidation state.
• Type III binary ionic compound: contains ions that are generated from non metals.

Answer to Problem 8A

Correct nomenclature of ${\text{TiO}}_2$ is Titanium(IV) oxide.

Explanation of Solution

Rules set for constituting nomenclature of binary ionic compounds are as follows:

• Position of both cation and anion forming element has to be identified for idea of their oxidation state.
• Always the cationic species name is retained and placed first in nomenclature.
• After the cation name, anion name is placed with suffix ‘-ide’ at the end of its root name.
• The oxidation state is expressed as roman numeral after cation name, enclosed in bracket.

In ${\text{TiO}}_2$ the metal Ti is in $+4$ oxidation state so IV is used in brackets after the metal name. ${\text{O}}^2{}^{-}$ is named as oxide. So Titanium(IV) oxide is the correct nomenclature.

(c)

Interpretation Introduction

Interpretation: Correct nomenclature of ${\text{CoCl}}_2$ with appropriate roman numerals must be provided.

Concept introduction: An ionic compound that contains only two elements, one present as a cation and one as an anion, is called a binary ionic compound. These compounds are of three types:

• Type I binary ionic compound: which contain ions of metals that can show only one type of oxidation state.
• Type II binary ionic compound: which contain ions of metals that can show more than one type of oxidation state.
• Type III binary ionic compound: contains ions that are generated from non metals.

Answer to Problem 8A

Correct nomenclature of ${\text{CoCl}}_2$ is Cobalt(II) chloride.

Explanation of Solution

Rules set for constituting nomenclature of binary ionic compounds are as follows:

• Position of both cation and anion forming element has to be identified for idea of their oxidation state.
• Always the cationic species name is retained and placed first in nomenclature.
• After the cation name, anion name is placed with suffix ‘-ide’ at the end of its root name.
• The oxidation state is expressed as roman numeral after cation name, enclosed in bracket.

In ${\text{CoCl}}_2$ the metal Co is in $+2$ oxidation state so II is used in brackets after the metal name. ${\text{Cl}}^{-}$ is named as chloride. So cobalt(II) chloride is the correct nomenclature.

(d)

Interpretation Introduction

Interpretation: Correct nomenclature of ${\text{Cr}}_2{\text{O}}_3$ with appropriate roman numerals must be provided.

Concept introduction: An ionic compound that contains only two elements, one present as a cation and one as an anion, is called a binary ionic compound. These compounds are of three types:

• Type I binary ionic compound: which contain ions of metals that can show only one type of oxidation state.
• Type II binary ionic compound: which contain ions of metals that can show more than one type of oxidation state.
• Type III binary ionic compound: contains ions that are generated from non metals.

Answer to Problem 8A

Correct nomenclature of ${\text{Cr}}_2{\text{O}}_3$ is Chromium(III) oxide.

Explanation of Solution

Rules set for constituting nomenclature of binary ionic compounds are as follows:

• Position of both cation and anion forming element has to be identified for idea of their oxidation state.
• Always the cationic species name is retained and placed first in nomenclature.
• After the cation name, anion name is placed with suffix ‘-ide’ at the end of its root name.
• The oxidation state is expressed as roman numeral after cation name, enclosed in bracket.

In ${\text{Cr}}_2{\text{O}}_3$ the metal Cr is in $+3$ oxidation state so III is used in brackets after the metal name. ${\text{O}}^2{}^{-}$ is named as oxide. So Chromium(III) oxide is the correct nomenclature.

(e)

Interpretation Introduction

Interpretation: Correct nomenclature of $\text{FeS}$ with appropriate roman numerals must be provided.

Concept introduction: An ionic compound that contains only two elements, one present as a cation and one as an anion, is called a binary ionic compound. These compounds are of three types:

• Type I binary ionic compound: which contain ions of metals that can show only one type of oxidation state.
• Type II binary ionic compound: which contain ions of metals that can show more than one type of oxidation state.
• Type III binary ionic compound: contains ions that are generated from non metals.

Answer to Problem 8A

Correct nomenclature of $\text{FeS}$ is Iron(II) sulfide.

Explanation of Solution

Rules set for constituting nomenclature of binary ionic compounds are as follows:

• Position of both cation and anion forming element has to be identified for idea of their oxidation state.
• Always the cationic species name is retained and placed first in nomenclature.
• After the cation name, anion name is placed with suffix ‘-ide’ at the end of its root name.
• The oxidation state is expressed as roman numeral after cation name, enclosed in bracket.

In $\text{FeS}$ the metal Fe is in $+2$ oxidation state so II is used in brackets after the metal name. ${\text{S}}^{2-}$ is named as sulfide. So Iron(II) sulfide is the correct nomenclature.

(f)

Interpretation Introduction

Interpretation: Correct nomenclature of ${\text{Cu}}_2\text{O}$ with appropriate roman numerals must be provided.

Concept introduction: An ionic compound that contains only two elements, one present as a cation and one as an anion, is called a binary ionic compound. These compounds are of three types:

• Type I binary ionic compound: which contain ions of metals that can show only one type of oxidation state.
• Type II binary ionic compound: which contain ions of metals that can show more than one type of oxidation state.
• Type III binary ionic compound: contains ions that are generated from non metals.

Answer to Problem 8A

Correct nomenclature of ${\text{Cu}}_2\text{O}$ is Copper(I) oxide.

Explanation of Solution

Rules set for constituting nomenclature of binary ionic compounds are as follows:

• Position of both cation and anion forming element has to be identified for idea of their oxidation state.
• Always the cationic species name is retained and placed first in nomenclature.
• After the cation name, anion name is placed with suffix ‘-ide’ at the end of its root name.
• The oxidation state is expressed as roman numeral after cation name, enclosed in bracket.

In ${\text{Cu}}_2\text{O}$ , the metal Cu is in $+1$ oxidation state so I is used in brackets after the metal name. Generally charge of mono-atomic cation is not specified but since Cu can show $+1\&+2$ both oxidation states, so here charge has to be specified. ${\text{O}}^2{}^{-}$ is named as oxide. So Copper(I) oxide is the correct nomenclature.