Question

What are the isomers of dibromobenzene?

Answer 1

The benzene parent molecule is `C_6H_6`. It is a high symmetry hexagon, which belongs to the `D_(6h)` point group. How many ways can I arrange 2 heteroatoms around the hexagon for `C_6H_4X_2`?

Explanation:

It doesn't take too much insight to realize that I can position the halides `1,2` (with respect to each other), `1,3`, or `1,4` - 3 isomers of dibromobenzene are thus possible. I urge you to sit down with a pencil and paper to confirm that this is correct.