Paraffin wax expands on melting. The melting point of wax will

Freezing paraffin wax will cause its particles to closely arrange, hence its volume reduces. While melting, its volume increases, because liquids generally take up more space than solids. And if you increase the pressure, it becomes harder to change into a state that needs more volume. So, more energy is needed, thus temperature, to melt. Hence, the melting point of paraffin wax is increased with pressure.