12.3

The page appears to be from a chemistry textbook, specifically focusing on aromatic compounds and isomers. Here is a summary of the tasks:

1. Name the compounds:

   • The text provides several structures to name.

2. Chemical formulas:

   • Task 2: Write the structural formulas of possible isomers for a given compound with iodine.
   • Task 3: Write the structural formulas of possible isomers for a given compound with chlorine.
   • Task 4: Write the structural formulas of possible isomers for a compound with both bromine and iodine.

For these tasks, you'll need to understand IUPAC naming conventions and how to identify and draw isomers of aromatic compounds.