Chapter 23, Problem 47A

Interpretation Introduction

Interpretation: To arrange the given compounds in the descending order of their boiling points that is from the compound having a lower boiling point to the compound containing a higher boiling point.

Concept Introduction: The boiling point of the compound depends upon the mass as well as the intermolecular forces of attraction. As the mass of the compound increases, the boiling point also increases. If the intermolecular forces of attraction are weak, then the compound will also have a lower boiling point.

Answer to Problem 47A

C< A< B

Explanation of Solution

The compounds given contain alkane, aldehydes, and alcohol. When the masses that are given are considered it is clear that the alcohol has the highest mass and the alkanes, as well as aldehydes, have similar masses. Therefore, alcohol will have the highest boiling point. When alkanes are considered, it has van der Waals forces of attraction. Aldehydes have dipole-dipole interactions and the alcohols have hydrogen bonding. Since weak intermolecular forces will have lower boiling points alkanes will have lower boiling points than aldehydes which have lower boiling points than alcohols.

Conclusion

The boiling point is also affected by several other factors like pressure, the effect of impurities, and also the branching of the alkyl chain. All these factors will affect the boiling point of a compound.