Chapter 5, Problem 28CR

(a)

Interpretation Introduction

Interpretation : The name of the polyatomic ion ${\text{NH}}_4^{+}$ needs to be determined.

Concept Introduction : The polyatomic ions are charged species; they can be positive or negative depending on the nature of molecule. They are also called molecular ions. In polyatomic ions, as the name suggest, two or more atoms are bonded together with covalent bond and considered as a single unit.

The naming of polyatomic ions follow two rules as follows:

A prefix bi can be used at the place of hydrogen when it is added to the formula of an ion. The charge of the ion increases by +1. For example: ${\text{CO}}_3^{2-}$ is carbonate ion and ${\text{HCO}}_3^{-}$ is bicarbonate ion.

Second rule check for the number of oxygen atoms in the ion. The base name is -ate ion, if prefix per- is added that means oxygen is added in the formula of ion. The change from -ate to -ite means reduction of oxygen in the formula. If two oxygen atoms are reduced, the prefix hypo is also added to the name. The rules work for phosphate, nitrate, sulfate and chlorate ions.

Answer to Problem 28CR

Ammonium ion.

Explanation of Solution

Ammonia will accept protons, i.e. hydrogen ions, in order to form ammonium ion.

(b)

Interpretation Introduction

Interpretation : The name of the polyatomic ion ${\text{SO}}_3^{2-}$ needs to be determined.

Concept Introduction : The polyatomic ions are charged species, they can be positive or negative depending on the nature of molecule. They are also called molecular ions. In polyatomic ions, as the name suggest, two or more atoms are bonded together with covalent bond and considered as a single unit.

The naming of polyatomic ions follow two rules as follows:

A prefix bi can be used at the place of hydrogen when it is added to the formula of an ion. The charge of the ion increases by +1. For example: ${\text{CO}}_3^{2-}$ is carbonate ion and ${\text{HCO}}_3^{-}$ is bicarbonate ion.

Second rule check for the number of oxygen atoms in the ion. The base name is -ate ion, if prefix per- is added that means oxygen is added in the formula of ion. The change from -ate to -ite means reduction of oxygen in the formula. If two oxygen atoms are reduced, the prefix hypo is also added to the name. The rules work for phosphate, nitrate, sulfate and chlorate ions.

Answer to Problem 28CR

Sulfite ion.

Explanation of Solution

The central nonmetal is sulfur.

The bonded atoms are oxygen atoms,

For 3 oxygen atoms, the oxidation state of sulfur is +4 which is 2 less than the maximum oxidation state. Since, the charge of oxygen is -2 thus, it has one oxygen less for -ate suffix and the suffix -ite is used here.

Thus, name of the ion will be sulfite ion.

(c)

Interpretation Introduction

Interpretation : The name of the polyatomic ion ${\text{NO}}_3^{-}$ needs to be determined.

Concept Introduction : The polyatomic ions are charged species; they can be positive or negative depending on the nature of molecule. They are also called molecular ions. In polyatomic ions, as the name suggest, two or more atoms are bonded together with covalent bond and considered as a single unit.

The naming of polyatomic ions follow two rules as follows:

A prefix bi can be used at the place of hydrogen when it is added to the formula of an ion. The charge of the ion increases by +1. For example: ${\text{CO}}_3^{2-}$ is carbonate ion and ${\text{HCO}}_3^{-}$ is bicarbonate ion.

Second rule check for the number of oxygen atoms in the ion. Considering anions of chlorine, the base name is -ate ion, if prefix per- is added that means oxygen is added in the formula of ion. The change from -ate to -ite means reduction of oxygen in the formula. If two oxygen atoms are reduced, the prefix hypo is also added to the name. The rules work for phosphate, nitrate, sulfate and chlorate ions. The base name is taken by considering the number of oxygen atoms attached to central metal so that central metal has maximum oxidation state. Thus, number of oxygen atoms in -ate anions may vary with central metal.

Answer to Problem 28CR

Nitrate ion.

Explanation of Solution

The central nonmetal is nitrogen.

The bonded atoms are oxygen atoms, for 3 oxygen atoms, the oxidation state of nitrogen is 5 here which is maximum oxidation state for nitrogen thus, suffix -ate is used.

Thus, the name of nitrate ion.

(d)

Interpretation Introduction

Interpretation : The name of the polyatomic ion ${\text{SO}}_4^{2-}$ needs to be determined.

Concept Introduction : The polyatomic ions are charged species; they can be positive or negative depending on the nature of molecule. They are also called molecular ions. In polyatomic ions, as the name suggest, two or more atoms are bonded together with covalent bond and considered as a single unit.

The naming of polyatomic ions follow two rules as follows:

A prefix bi can be used at the place of hydrogen when it is added to the formula of an ion. The charge of the ion increases by +1. For example: ${\text{CO}}_3^{2-}$ is carbonate ion and ${\text{HCO}}_3^{-}$ is bicarbonate ion.

Second rule check for the number of oxygen atoms in the ion. The base name is -ate ion, if prefix per- is added that means oxygen is added in the formula of ion. The change from -ate to -ite means reduction of oxygen in the formula. If two oxygen atoms are reduced, the prefix hypo is also added to the name. The rules work for phosphate, nitrate, sulfate and chlorate ions.

Answer to Problem 28CR

Sulfate ion.

Explanation of Solution

The central nonmetal is sulfur.

The bonded atoms are oxygen atoms,

For 4 oxygen atoms, the oxidation state of sulfur is +6 which is the maximum oxidation state. Thus, suffix -ate is used.

Thus, name of the ion will be sulfate ion.

(e)

Interpretation Introduction

Interpretation : The name of the polyatomic ion ${\text{NO}}_2^{-}$ needs to be determined.

Concept Introduction : The polyatomic ions are charged species; they can be positive or negative depending on the nature of molecule. They are also called molecular ions. In polyatomic ions, as the name suggest, two or more atoms are bonded together with covalent bond and considered as a single unit.

The naming of polyatomic ions follow two rules as follows:

A prefix bi can be used at the place of hydrogen when it is added to the formula of an ion. The charge of the ion increases by +1. For example: ${\text{CO}}_3^{2-}$ is carbonate ion and ${\text{HCO}}_3^{-}$ is bicarbonate ion.

Second rule check for the number of oxygen atoms in the ion. The base name is -ate ion, if prefix per- is added that means oxygen is added in the formula of ion. The change from -ate to -ite means reduction of oxygen in the formula. If two oxygen atoms are reduced, the prefix hypo is also added to the name. The rules work for phosphate, nitrate, sulfate and chlorate ions.

Answer to Problem 28CR

Nitrite ion.

Explanation of Solution

The central nonmetal is nitrogen.

The bonded atoms are oxygen atoms, for 2 oxygen atoms, the oxidation state of nitrogen is 3 which is 2 less than the maximum oxidation state for nitrogen. The charge of oxygen is -2 thus, one oxygen atom is less thus, suffix -ite is used.

Thus, the name of nitrite ion.

(f)

Interpretation Introduction

Interpretation : The name of the polyatomic ion ${\text{CN}}^{-}$ needs to be determined.

Concept Introduction : The polyatomic ions are charged species; they can be positive or negative depending on the nature of molecule. They are also called molecular ions. In polyatomic ions, as the name suggest, two or more atoms are bonded together with covalent bond and considered as a single unit.

The naming of polyatomic ions follow two rules as follows:

A prefix bi can be used at the place of hydrogen when it is added to the formula of an ion. The charge of the ion increases by +1. For example: ${\text{CO}}_3^{2-}$ is carbonate ion and ${\text{HCO}}_3^{-}$ is bicarbonate ion.

Second rule check for the number of oxygen atoms in the ion. The base name is -ate ion, if prefix per- is added that means oxygen is added in the formula of ion. The change from -ate to -ite means reduction of oxygen in the formula. If two oxygen atoms are reduced, the prefix hypo is also added to the name. The rules work for phosphate, nitrate, sulfate and chlorate ions.

Answer to Problem 28CR

Cyanide ion.

Explanation of Solution

The central nonmetal is carbon.

The bonded atom isnitrogen atom. The oxidation state of nitrogen is +3 which is 2 less than the maximum oxidation state thus, suffix -ite is used and name of polyatomic ion will be carbon nitrite, commonly known as cyanide ion

(g)

Interpretation Introduction

Interpretation : The name of the polyatomic ion ${\text{OH}}^{-}$ needs to be determined.

Concept Introduction : The polyatomic ions are charged species; they can be positive or negative depending on the nature of molecule. They are also called molecular ions. In polyatomic ions, as the name suggest, two or more atoms are bonded together with covalent bond and considered as a single unit.

The naming of polyatomic ions follow two rules as follows:

A prefix bi can be used at the place of hydrogen when it is added to the formula of an ion. The charge of the ion increases by +1. For example: ${\text{CO}}_3^{2-}$ is carbonate ion and ${\text{HCO}}_3^{-}$ is bicarbonate ion.

Second rule check for the number of oxygen atoms in the ion. The base name is -ate ion, if prefix per- is added that means oxygen is added in the formula of ion. The change from -ate to -ite means reduction of oxygen in the formula. If two oxygen atoms are reduced, the prefix hypo is also added to the name. The rules work for phosphate, nitrate, sulfate and chlorate ions.

Answer to Problem 28CR

Hydroxide ion.

Explanation of Solution

The central nonmetal is hydrogen.

The bonded atom is oxygen thus, it is hydrogen oxide, commonly known as hydroxide ion.

(h)

Interpretation Introduction

Interpretation : The name of the polyatomic ion ${\text{ClO}}_4^{-}$ needs to be determined.

Concept Introduction : The polyatomic ions are charged species; they can be positive or negative depending on the nature of molecule. They are also called molecular ions. In polyatomic ions, as the name suggest, two or more atoms are bonded together with covalent bond and considered as a single unit.

The naming of polyatomic ions follow two rules as follows:

A prefix bi can be used at the place of hydrogen when it is added to the formula of an ion. The charge of the ion increases by +1. For example: ${\text{CO}}_3^{2-}$ is carbonate ion and ${\text{HCO}}_3^{-}$ is bicarbonate ion.

Second rule check for the number of oxygen atoms in the ion. The base name is -ate ion, if prefix per- is added that means oxygen is added in the formula of ion. The change from -ate to -ite means reduction of oxygen in the formula. If two oxygen atoms are reduced, the prefix hypo is also added to the name. The rules work for phosphate, nitrate, sulfate and chlorate ions.

Answer to Problem 28CR

Perchlorate ion.

Explanation of Solution

The central nonmetal is chlorine, the bonded atom is oxygen.The base for chlorine is -ate where chlorine has +5 oxidation state here, the oxidation state of chlorine is +7 thus, one oxygen is added that adds prefix per to the chlorate ion.

Therefore, name of the polyatomic ion will be perchlorate ion.

(i)

Interpretation Introduction

Interpretation : The name of the polyatomic ion ${\text{ClO}}^{-}$ needs to be determined.

Concept Introduction : The polyatomic ions are charged species; they can be positive or negative depending on the nature of molecule. They are also called molecular ions. In polyatomic ions, as the name suggest, two or more atoms are bonded together with covalent bond and considered as a single unit.

The naming of polyatomic ions follow two rules as follows:

A prefix bi can be used at the place of hydrogen when it is added to the formula of an ion. The charge of the ion increases by +1. For example: ${\text{CO}}_3^{2-}$ is carbonate ion and ${\text{HCO}}_3^{-}$ is bicarbonate ion.

Second rule check for the number of oxygen atoms in the ion. The base name is -ate ion, if prefix per- is added that means oxygen is added in the formula of ion. The change from -ate to -ite means reduction of oxygen in the formula. If two oxygen atoms are reduced, the prefix hypo is also added to the name. The rules work for phosphate, nitrate, sulfate and chlorate ions.

Answer to Problem 28CR

Hypochlorite ion.

Explanation of Solution

The central nonmetal is chlorine, the bonded atom is oxygen. The base for chlorine is -ate where chlorine has +5 oxidation state here, the oxidation state of chlorine is +1 thus, two oxygen atoms are removed that adds prefix hypo to the chlorite ion.

Therefore, name of the polyatomic ion will be hypochlorite ion.

(j)

Interpretation Introduction

Interpretation : The name of the polyatomic ion ${\text{PO}}_4^{3-}$ needs to be determined.

Concept Introduction : The polyatomic ions are charged species;they can be positive or negative depending on the nature of molecule. They are also called molecular ions. In polyatomic ions, as the name suggest, two or more atoms are bonded together with covalent bond and considered as a single unit.

The naming of polyatomic ions follow two rules as follows:

A prefix bi can be used at the place of hydrogen when it is added to the formula of an ion. The charge of the ion increases by +1. For example: ${\text{CO}}_3^{2-}$ is carbonate ion and ${\text{HCO}}_3^{-}$ is bicarbonate ion.

Second rule check for the number of oxygen atoms in the ion. The base name is -ate ion, if prefix per- is added that means oxygen is added in the formula of ion. The change from -ate to -ite means reduction of oxygen in the formula. If two oxygen atoms are reduced, the prefix hypo is also added to the name. The rules work for phosphate, nitrate, sulfate and chlorate ions.

Answer to Problem 28CR

Phosphate ion.

Explanation of Solution

The central nonmetal is phosphorus, the bonded atom is oxygen. The oxidation state of phosphorus is +5 which is maximum oxidation state. Thus, suffix -ate is used and name of polyatomic ion will be phosphate ion.