Question

2 of these 3 compunds are the same chemical compound? Circle which ones

Answer 1

in (b) the the left and centre are the same; in (c) it is the centre and right.

Explanation:

In (b) the right molecule has the hydroxyl groups in the 1&3 positions (meta arrangement). In the other two, they are in 1 & 2 (ortho arrangement).

In (c) if you create IUPAC names for the compounds, you will see that the centre and right molecules must have the same name. Both have a longest C chain of 6, a hydroxyl group on carbon 1 and a methyl group on carbons 2 and 4.