Chapter 12, Problem 52A

Interpretation Introduction

Interpretation:

The reason for dispersion forces to be weaker than dipole-dipole forces must be explained.

Concept introduction:

A molecule will be polar if the resultant of all bond moments in the molecule is non-zero.

Dispersion forces are generated in non-polar molecule.

Answer to Problem 52A

Dispersion forces are weaker as the molecules don’t have permanent dipole moment unlike polar molecules.

Explanation of Solution

In dipole-dipole interaction positive pole of one dipole interacts with negative pole of another dipole. This interaction is partially ionic. But in case of dispersion forces dipole moment is induced in non-polar molecules. As there is no permanent dipole moment the interaction is weaker.

Conclusion

Dispersion forces are weaker as it is generated due to induced dipole moment unlike polar molecules in which there is permanent dipole moment.