Chapter 11, Problem 73A

(a)

Interpretation Introduction

Interpretation:

To check whether the formula for ${\text{K}}_2\text{Br}$ ionic compound is correct or not. If incorrect then, write the correct formula.

Concept Introduction:

A chemical compound which is composed of ions that are hold together by electrostatic forces is called as ionic compound.

Answer to Problem 73A

The formula for ${\text{K}}_2\text{Br}$ is incorrect and correct formula is $\text{KBr}$

Explanation of Solution

The valency of Potassium ion is $+1$ and valency of Bromide ion is $-1$. The formula of an ionic compound can be written by following two steps:

1. Write the cation first and then anion.
2. Exchange the valency of both the ions.

Hence, the formula can be written as : $\text{KBr}$

Therefore, the formula for potassium bromide ${\text{K}}_2\text{Br}$ is incorrect and correct formula is $\text{KBr}$

(b)

Interpretation Introduction

Interpretation:

To check whether the formula for ${\text{Na}}_{\text{2}}\text{S}$ ionic compound is correct or not. If incorrect then, write the correct formula.

Concept Introduction:

A chemical compound which is composed of ions that are hold together by electrostatic forces is called as ionic compound.

Answer to Problem 73A

The formula for ${\text{Na}}_{\text{2}}\text{S}$ is correct.

Explanation of Solution

The valency of Sodium ion is $+1$ and valency of Sulfide ion is $-2$. The formula of an ionic compound can be written by following two steps:

1. Write the cation first and then anion.
2. Exchange the valency of both the ions.

Hence, the formula can be written as : ${\text{Na}}_{\text{2}}\text{S}$

The formula for sodium sulfide ${\text{Na}}_{\text{2}}\text{S}$ is correct.

(c)

Interpretation Introduction

Interpretation:

To check whether the formula for ${\text{CaN}}_{\text{2}}$ ionic compound is correct or not. If incorrect then, write the correct formula.

Concept Introduction:

A chemical compound which is composed of ions that are hold together by electrostatic forces is called as ionic compound.

Answer to Problem 73A

The formula for ${\text{CaN}}_{\text{2}}$ is incorrect and correct formula is ${\text{Ca}}_3{\text{N}}_{\text{2}}$

Explanation of Solution

The valency of Calcium ion is $+2$ and valency of Nitride ion is $-3$. The formula of an ionic compound can be written by following two steps:

1. Write the cation first and then anion.
2. Exchange the valency of both the ions.

Hence, the formula can be written as : ${\text{Ca}}_3{\text{N}}_{\text{2}}$

Therefore, the correct formula for calcium nitride is ${\text{Ca}}_3{\text{N}}_{\text{2}}$ .

(d)

Interpretation Introduction

Interpretation:

To check whether the formula for ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}$ ionic compound is correct or not. If incorrect then, write the correct formula.

Concept Introduction:

A chemical compound which is composed of ions that are hold together by electrostatic forces is called as ionic compound.

Answer to Problem 73A

The formula for ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}$ is correct.

Explanation of Solution

The valency of Aluminum ion is $+3$ and valency of Oxide ion is $-2$. The formula of an ionic compound can be written by following two steps:

1. Write the cation first and then anion.
2. Exchange the valency of both the ions.

Hence, the formula can be written as : ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}$

Therefore, the formula for Aluminum oxide ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}$ is correct.