Chapter 9, Problem 9.27QP

(a)

Interpretation Introduction

Interpretation: The bond angle of the given ions is to be determined.

Concept introduction: The bond angle of the given molecule is determined by its geometry which is determined by the number of atoms and lone pair of electrons present around the central atom.

To determine: The bond angle of the molecule ${\text{NH}}_4^{+}$.

Answer to Problem 9.27QP

Solution

The bond angle of ${\text{NH}}_4^{+}$ molecule is $\underset{\_}{109.5°}$.

Explanation of Solution

Explanation

The number of bond pairs and lone pairs present around the central atom is determined by the Lewis structure of the molecule. The Lewis structure of ${\text{NH}}_4^{+}$ molecule is,

Figure 1

The number of bond pairs present around the central atom is four and zero lone pairs in the given structure of ${\text{NH}}_4^{+}$. Therefore, the molecular geometry of the ${\text{NH}}_4^{+}$ is tetrahedral with bond angle $\underset{\_}{109.5°}$.

(b)

Interpretation Introduction

To determine: The bond angle of the molecule ${\text{SO}}_3^{2-}$.

Answer to Problem 9.27QP

Solution

The bond angle of ${\text{SO}}_3^{2-}$ molecule is less than $\underset{\_}{109.5°}$.

Explanation of Solution

Explanation

The number of bond pairs and lone pairs present around the central atom is determined by the Lewis structure of the molecule. The Lewis structure of ${\text{SO}}_3^{2-}$ molecule is,

Figure 2

The number of bond pairs present around the central atom is three and one lone pairs in the given structure of ${\text{SO}}_3^{2-}$. Therefore, the molecular geometry of the ${\text{SO}}_3^{2-}$ is tetrahedral with bond angle less than $\underset{\_}{109.5°}$.

(c)

Interpretation Introduction

To determine: The bond angle of the molecule ${\text{NO}}_2^{-}$.

Answer to Problem 9.27QP

Solution

The bond angle of ${\text{NO}}_2^{-}$ molecule is less than $\underset{\_}{120°}$.

Explanation of Solution

Explanation

The number of bond pairs and lone pairs present around the central atom is determined by the Lewis structure of the molecule. The Lewis structure of ${\text{NO}}_2^{-}$ molecule is,

Figure 3

The number of bond pairs present around the central atom is two and two lone pairs in the given structure of ${\text{NO}}_2^{-}$. Therefore, the molecular geometry of the ${\text{NO}}_2^{-}$ is trigonal planar with bond angle less than $\underset{\_}{120°}$ .

(d)

Interpretation Introduction

To determine: The bond angle of the molecule ${\text{XeF}}_5^{+}$.

Answer to Problem 9.27QP

Solution

The bond angle of ${\text{XeF}}_5^{+}$ molecule is $\underset{\_}{90°}$.

Explanation of Solution

Explanation

The number of bond pairs and lone pairs present around the central atom is determined by the Lewis structure of the molecule. The Lewis structure of ${\text{XeF}}_5^{+}$ molecule is,

Figure 4

The number of bond pairs present around the central atom is five and one lone pairs in the given structure of ${\text{XeF}}_5^{+}$. Therefore, the molecular geometry of the ${\text{XeF}}_5^{+}$ is octahedral with bond angle $\underset{\_}{90°}$.

Conclusion

1. a. The bond angle of ${\text{NH}}_4^{+}$ molecule is $\underset{\_}{109.5°}$.
2. b. The bond angle of ${\text{SO}}_3^{2-}$ molecule is less than $\underset{\_}{109.5°}$.
3. c. The bond angle of ${\text{NO}}_2^{-}$ molecule is less than $\underset{\_}{120°}$.
4. d. The bond angle of ${\text{XeF}}_5^{+}$ molecule is $\underset{\_}{90°}$.