question_answer 31)

Write down the products of ozonolysis of 1, 2-dimethylbenzene (o-xylene). How does the result support Kekule structure of benzene?

Answer:

o-xylene may be regarded as a resonance hybrid of the following two Kekule structures (A) and (B). Ozonolysis of each one of these gives two products. For example,   Thus, in all three products are obtained by the ozonolysis of o-xylene (i.e., glyoxal, methyl glyoxal and dimethyl glyoxal). Since, all the three products cannot be obtained from any one of the two Kekule structures, (A) and (B), this shows that o-xylene is a resonance hybrid of the two Kekule structures, (A) and (B).