Mono chlor toluene

Isomerism.— As all of the second group, in which substitution occurs in the side chain, considered as benzene derivatives, are mono-substituted benzenes, they do not exist in isomeric forms, and only one compound of each formula is known. The first group, however, in which halogen substitution occurs in the ring, are all poly-substitution products of benzene, since toluene itself is a mono-substituted benzene. Mono-chlor toluene is, therefore, a di-substituted benzene, and occurs in the three forms, as follows ... 

The mono-nitro toluenes, like the mono-chlor toluenes being di-substituted benzenes, are known in the three isomeric forms. 

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