List each set of compounds in order of increasing boiling point.
(a) hexane, octane, and decane
Solution 10P :
Here, we have to list each set of compounds in order of increasing boiling point :
To determine the boiling point of the compound, we look at the molecular weight of the compound, the branching of the compound and the bonds or the forces acting on the compound.
(a) hexane, octane, and decane :
Alkanes have the hydrogen bonds between them. Since all the compounds given are alkanes and has no additional groups present on them, we don’t consider the bonding force acting on the compounds, but we will use molecular weights to determine the boiling point of the given compounds.
The molecular weight of hexane is 86 g and the molecular weight of octane is 114 g and the molecular weight of decane is 142 g.
As we see, the molecular weight of the hexane has got the lowest molecular weight and decane has got the highest molecular weight. Higher the molecular weight, higher is the boiling point and hence the order of compounds in the increasing order of boiling point is :
Hexane < Octane < Decane
Hexane has the lowest boiling point and decane has the highest boiling point among the given compounds.