Chapter 1, Problem 48P

(a)

Interpretation Introduction

Interpretation:Two resonance forms for ${\left({\text{CH}}_{\text{3}}\right)}_2\text{BN}{\left({\text{CH}}_{\text{3}}\right)}_2$ , ${\left({\text{CH}}_{\text{3}}\right)}_2{\text{BOCH}}_{\text{3}}$ and ${\left({\text{CH}}_{\text{3}}\right)}_2\text{BF}$ should be formulated.

Concept introduction:When a certain Lewis structure proposed is not able to describe all the experimentally observed parameters of a molecule two or more Lewis structures that differ only in the location of multiple bonds are drawn. These are known as resonance structures. The actual molecule is essentially represented as the hybrid of each of such resonance structures. For instance, a molecule such as ozone ${\text{O}}_3$ the resonance structure and hybrid are illustrated below.

  

(b)

Interpretation Introduction

Interpretation:Out of the two resonanceformsof ${\left({\text{CH}}_{\text{3}}\right)}_2\text{BN}{\left({\text{CH}}_{\text{3}}\right)}_2$ , ${\left({\text{CH}}_{\text{3}}\right)}_2{\text{BOCH}}_{\text{3}}$ and ${\left({\text{CH}}_{\text{3}}\right)}_2\text{BF}$ , more important form should be formulated.

Concept introduction: When a certain Lewis structure proposed is not able to describe all the experimentally observed parameters of a molecule two or more Lewis structures that differ only in the location of multiple bonds are drawn. These are known as resonance structures. The actual molecule is essentially represented as the hybrid of each of such resonance structures. For instance, a molecule such as ozone ${\text{O}}_3$ the resonance structure and hybrid are illustrated below.

  

(c)

Interpretation Introduction

Interpretation:The manner the relative importance of the resonance forms ${\left({\text{CH}}_{\text{3}}\right)}_2\text{BN}{\left({\text{CH}}_{\text{3}}\right)}_2$ , ${\left({\text{CH}}_{\text{3}}\right)}_2{\text{BOCH}}_{\text{3}}$ and ${\left({\text{CH}}_{\text{3}}\right)}_2\text{BF}$ is affected by the electronegativity differences in nitrogen, oxygen, and fluorine should be determined.

Concept introduction: When a certain Lewis structure proposed is not able to describe all the experimentally observed parameters of a molecule two or more Lewis structures that differ only in the location of multiple bonds are drawn. These are known as resonance structures. The actual molecule is essentially represented as the hybrid of each of such resonance structures. For instance, a molecule such as ozone ${\text{O}}_3$ the resonance structure and hybrid are illustrated below.

  

(d)

Interpretation Introduction

Interpretation: The hybridization of nitrogen in ${\left({\text{CH}}_{\text{3}}\right)}_2\text{BN}{\left({\text{CH}}_{\text{3}}\right)}_2$ and oxygen in ${\left({\text{CH}}_{\text{3}}\right)}_2{\text{BOCH}}_{\text{3}}$ should be predicted.

Concept introduction:The table that relates the steric number with hybridization is as follows:

  $\begin{array}{cc}\text{Steric Number}& \text{Type of Hybridisation}\\ 2& \text{sp}\\ 3& {\text{sp}}^2\\ 4& {\text{sp}}^3\\ 5& {\text{sp}}^3\text{d}\\ 6& {\text{sp}}^3{\text{d}}^2\end{array}$