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.