(a) When a mixture containing one mole each of the three dimethylbenzenes (o-, m-, and p-xylene) is treated with one mole of chlorine in the presence of a Lewis acid catalyst, one of the three hydrocarbons is monochlorinated in 100% yield, whereas the other two remain completely unreacted. Which isomer reacts? Explain the differences in reactivity. 

(b) The same experiment carried out on a mixture of the following three trimethylbenzenes gives a similar outcome. Answer the questions posed in (a) for this mixture of compounds. 

Transcribed Image Text:

CH3 CH3 CH3 CH3 CH3 CH3 H;C CH3 CH3 1,2,3-Trimethylbenzene 1,2,4-Trimethylbenzene 1,3,5-Trimethylbenzene