Chapter 3, Problem 3F.6E

(a)

Interpretation Introduction

Interpretation:

Whether ${\text{H}}_2\text{S}$ or ${\text{H}}_2\text{Se}$ has higher normal melting point has to be determined.

Concept Introduction:

Dipole-dipole interactions come into play when partial charges of different dipoles interact with each other. Higher polarity between molecules, more will be dipole-dipole interactions between them and vice-versa. Boiling point is governed by strength of dipole-dipole interactions that is measured in terms of dipole moments. Boiling point is directly related to dipole moment of molecules. More dipole moment of molecules, higher will be boiling point and vice-versa.

(b)

Interpretation Introduction

Interpretation:

Whether $\text{NaCl}$ or ${\text{CH}}_3\text{Cl}$ has higher normal melting point has to be determined.

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

Whether ${\text{NH}}_3$ or ${\text{PH}}_{\text{3}}$ has higher normal melting point has to be determined.

Concept Introduction:

Refer to part (a).

(d)

Interpretation Introduction

Interpretation:

Whether ${\text{SiH}}_4$ or ${\text{SiF}}_4$ has higher normal melting point has to be determined.

Concept Introduction:

Refer to part (a).