Physical Properties of Arenes
Physical State and Odour of Arenes
Arenes up to eight carbon atoms are colourless liquids with characteristic odour. Higher members are solids.
Solubility of Arenes
Arenes are insoluble in water due to the presence of long hydrocarbon part (benzene ring) but fairly soluble in organic solvents.
Melting and Boiling Point of Arenes
The boiling points and melting points of arenes increase with increase in the mass due to the corresponding increase in the magnitude of van der Waal's forces of attraction. However, it may be noted that the melting point of benzene is higher than that of methylbenzene (toluene) because the molecules of benzene are closely packed in the crystal lattice which is not the case in toluene. Among isomeric arenes, p-isomers usually have higher melting point than the corresponding ortho and meta isomers which is again due to the fact that para-isomers being the most symmetrical fit closely in the crystal lattice.