Chapter 8, Problem 134A

Interpretation Introduction

Interpretation:

The sigma bond, pi bond, and lone pairs present in the urea are to be identified.

Concept introduction:

In the molecular formula, the element symbols and the subscripts number tells the type and the number of each atom in a molecule. In structural formula method, the atoms of each element are depicted by letter symbols and bond is used to show relative position.

Answer to Problem 134A

The $\text{N}-\text{H}$ bonds, $\text{C}-\text{N}$ bonds, and one of the $\text{C}-\text{O}$ bonds are sigma bonds. The other $\text{C}-\text{O}$ bond is pi bond. The lone pairs are present on N and O atoms.

Explanation of Solution

The structure of acetonitrile is shown below.

It is known that in single bond only sigma bond is present. In double bond, one bond is sigma and one is pi bond. In triple bond, one bond is sigma and the remaining two bonds are pi bond. The lone pairs are non bonding electrons represented by two dots.

Therefore, the representation of sigma bonds, pi bonds, and lone pairs are shown below.

Therefore, $\text{N}-\text{H}$ bonds, $\text{C}-\text{N}$ bonds, and one of the $\text{C}-\text{O}$ bonds are sigma bonds. The other $\text{C}-\text{O}$ bond is pi bond. The lone pairs are present on N and O atoms.

Conclusion

The $\text{N}-\text{H}$ bonds, $\text{C}-\text{N}$ bonds, and one of the $\text{C}-\text{O}$ bonds are sigma bonds. The other $\text{C}-\text{O}$ bond is pi bond. The lone pairs are present on N and O atoms.