Describe and explain the effects of boiling points of alkane when increasing the chain length and increasing the branching of the alkane.

As the length of an alkane chain increases, the boiling point increases. This is because there are more points of contact with each adjacent molecule. This means there are stronger induced dipole to dipole forces between adjacent molecules. So more energy is required to overcome these forces hence the boiling point is higher. For example: propane will have a lower boiling point than butane. As the branching of an alkane increases, the boiling point decreases. This is because the points of contact with adjacent molecules decreases. So there are weaker dipole to dipole forces and less energy is required to overcome these forces hence the boiling point decreases. For example: 2-methyl-butane will have a lower boiling point than pentane also 2,2-dimethyl-propane will have a lower melting point than 2-methyl-butane.