Chapter 5, Problem 31QAP

Interpretation Introduction

(a)

Interpretation:

The formula of the compounds should be determined.

Concept Introduction:

The formula of compounds is written by crisscross method, according to this method, charge or oxidation state of one ion/polyatomic ion becomes subscript of another ion and vice versa.

For example: In aluminum chloride, the charge on Al ion is +3 and that on Cl ion is -1 thus, by crisscross method, formula of compound will be ${\text{AlCl}}_{\text{3}}$.

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 31QAP

${\text{MgCl}}_2$

Explanation of Solution

Magnesium chloride is an ionic compound. The symbol for magnesium is Mg and that for chlorine is Cl. Here, magnesium has +2 charge and chlorine has -1 charge thus, by crisscross method, the formula of compound will be ${\text{MgCl}}_{\text{2}}$

Interpretation Introduction

(b)

Interpretation:

The formula of the compounds should be determined.

Concept Introduction:

The formula of compounds is written by crisscross method, according to this method, charge or oxidation state of one ion/polyatomic ion becomes subscript of another ion and vice versa.

For example: In aluminum chloride, the charge on Al ion is +3 and that on Cl ion is -1 thus, by crisscross method, formula of compound will be ${\text{AlCl}}_{\text{3}}$.

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 31QAP

${\text{Ca(ClO)}}_2$

Explanation of Solution

The given name is calcium hypochlorite.

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.

For the base value, number of oxygen atoms attached to chlorine are 3, according to above explanation for suffix -hypo if 2 oxygen atoms are reduced the formula become ${\text{ClO}}^{-}$

The symbol for calcium atom is Ca and it has +2 charge thus, according to crisscross method, the formula of compound will be ${\text{Ca(ClO)}}_{\text{2}}$

Interpretation Introduction

(c)

Interpretation:

The formula of the compounds should be determined.

Concept Introduction:

The formula of compounds is written by crisscross method, according to this method, charge or oxidation state of one ion/polyatomic ion becomes subscript of another ion and vice versa.

For example: In aluminum chloride, the charge on Al ion is +3 and that on Cl ion is -1 thus, by crisscross method, formula of compound will be ${\text{AlCl}}_{\text{3}}$.

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 31QAP

${\text{KClO}}_3$

Explanation of Solution

The name of the compound is potassium chlorate.

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 number of oxygen atoms in chlorate anion is 3 thus, formula of chlorate will be ${\text{ClO}}_3{}^{-}$

The symbol for potassium atom is K. The charge on atom is +1 thus, according to crisscross method, the formula of compound will be ${\text{KClO}}_3$.

Interpretation Introduction

(d)

Interpretation:

The formula of the compounds should be determined.

Concept Introduction:

The formula of compounds is written by crisscross method, according to this method, charge or oxidation state of one ion/polyatomic ion becomes subscript of another ion and vice versa.

For example: In aluminum chloride, the charge on Al ion is +3 and that on Cl ion is -1 thus, by crisscross method, formula of compound will be ${\text{AlCl}}_{\text{3}}$.

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 31QAP

${\text{Ba(ClO}}_{\text{4}}{\text{)}}_{\text{2}}$

Explanation of Solution

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 number of oxygen atoms attached to chlorine in base name are 3 for suffix -per, one more oxygen is added thus, formula become ${\text{ClO}}_4{}^{-}$.

The symbol for barium is Ba, the charge is +2 thus, formula of compound by crisscross method will be ${\text{Ba(ClO}}_{\text{4}}{\text{)}}_{\text{2}}$.