How do you differentiate between para-xylene and ortho-xylene?

Answer 1

Probably the easiest way is to take an NMR and look at the aromatic region (7-8 chemical shift).  p-xylene has 4 equivalent aromatic protons (giving only 1 peak in the 7-8 region), but o-xylene has two pairs of equivalent protons (giving 2 peaks in the 7-8 region).

Answer 2

Para-xylene and ortho-xylene are isomers of xylene, a common solvent and precursor in the chemical industry. They can be differentiated based on their molecular structures, with para-xylene having its two methyl groups on opposite sides of the benzene ring, and ortho-xylene having them on adjacent carbon atoms. This difference leads to distinct physical and chemical properties, which can be used for separation and identification.