2 traditional nomenclature of toluene

A. There are four isomers of aromatic hydrocarbon with molecular formula C8H 10: ethylbenzene, o-xylene, m-xylene and p-xylene; There are three bromine substituents on the benzene ring of ethylbenzene, two bromine substituents on the benzene ring of o-xylene, three bromine substituents on the benzene ring of m-xylene and 1 bromine substituent on the benzene ring.

B, xylene according to the customary naming method named o-xylene, m-xylene, p-xylene, so b is correct;

C, xylene can also be named by system method, such as o-xylene system naming method: 1, 2- xylene, so c is correct;

D, the molecular formula of aromatic hydrocarbon is C8H 10, and there are four isomers of ethylbenzene, o-xylene, m-xylene and p-xylene, so D is wrong;

So choose ad.