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

The term xylene refers to a mixture of three aromatic hydrocarbon isomers essentially benzene derivatives, which encompasses ortho-, meta-, and para- isomers of dimethyl benzene.

OSHA (plant safety) and the EPA (plant emissions), plus the state and local equivalents of those two agencies, would control xylene production.

Positioning around a benzene ring relative to the major functional group. Para is opposite, ortho is next to, meta is in between.

No because it is not an element. It is a mixture of 3 aromatic isomers found in crude oil.

para-xylene (1,4 dimethybenzene): so the answer is two sets of equivalent proton