Chapter 10, Problem 10.70P

(a)

Interpretation Introduction

Interpretation:

The molecular shape and ideal bond angle around each carbon atom in propylene oxide is to be determined.

Concept introduction:

The following steps are used to determine the molecular shape of the given molecule.

Step 1: Write the Lewis structure of the given formula and place the atoms.

Step 2: Count all electron groups including bonding and non-bonding pairs around the central atom and use it to assign one of the five electron-group arrangement.

Step 3: Write the ideal bond angle related to the electron-group arrangement and the effect of any deviation can be predicted by using VSEPR.

Step 4: Count the bonding and non-bonding electron groups and draw the molecular shape accordingly.

(b)

Interpretation Introduction

Interpretation:

Deviation in the angle of $\text{C}-\text{C}-\text{C}$ bond angle from the ideal bond angle is to be determined.

Concept introduction:

VSEPR theory is based on the repulsions between the electrons pair in the valence shell. According to VSEPR theory, the shape of a molecule depends on the position of the electron pairs to minimize the repulsion, and maximize the stability.

According to VSEPR theory, the table for molecular geometries when the central atom has no lone pair is as follows:

$\begin{array}{cc}\text{Electron}\text{groups}& \text{Geometry}\\ \text{2}& \text{Linear}\\ \text{3}& \text{Trigonal}\text{Planar}\\ \text{4}& \text{Tetrahedral}\\ \text{5}& \text{Trigonal}\text{bipyramidal}\\ \text{6}& \text{Octahedral}\end{array}$