Chapter 4, Problem 10CTQ

a)

Interpretation Introduction

Interpretation: Molecule that makes the weakest intermolecular attachments to neighboring molecules should be determined.

Concept introduction: Intermolecular forces are types of forces that are responsible to hold atoms together in a molecule.

There are various types of intermolecular forces as follows:

1. Hydrogen bonding:

As is evident from its name, these types of forces exist if hydrogen is present. Such forces are present when hydrogen atom bonds with highly electronegative elements like N, O, F. It is of two types: intramolecular and intermolecular. $\text{HF}$ forms hydrogen bonding with water.

2. Ion-dipole forces:

This force exists between ion and molecules with dipole moment in them. Attraction exists between ion and oppositely charged end of the dipole.

3. Ion-induced dipole forces:

When an ion approaches a non-polar molecule, it induces a temporary dipole in it. Ion gets attracted to the oppositely charged part of the dipole induced in the molecule.

4. Induced dipole-induced dipole attraction:

These forces are also known as London dispersion forces or van der Waals forces. Such forces are present between various atoms and molecules. These are observed generally in non-polar molecules, halogens and noble gases.

b)

Interpretation Introduction

Interpretation: Whether dipole moment trends with boiling points for propanal $\text{1-chloropropane}$ and butane or not should be determined.

Concept introduction: Dipole moment is the measure of bond polarity in the molecule. It is defined as the product of charge and distance of separation between opposite charges. Polar molecules consist of dipole moments due to the presence of charges in them whereas non-polar molecules do not have dipole moments. Boiling is used to define when a substance gets converted from its liquid to the vapor phase at the boiling point. The temperature at which the vapor pressure of the liquid becomes equal to atmospheric pressure is called the boiling point.