Final answer:
Anisole, when heated with concentrated hydroiodic acid, undergoes cleavage of the methoxy group leading to the formation of phenol and iodomethane, not iodobenzene or methanol.
Step-by-step explanation:
When anisole is heated with concentrated hydroiodic acid (HI), the reaction leads to the cleavage of the methoxy group (-OCH3) and the substitution of hydrogen or iodine at the oxygen's position. The correct product of this reaction is phenol and iodomethane, as the methoxy group is replaced with iodine to form iodomethane and the remaining aromatic ring gains a hydroxyl group forming phenol. This reaction is an example of a cleavage of ether in acidic conditions.
Concentrated hydroiodic acid is a strong nucleophile as well as a good source of hydronium ions, which can protonate the ether oxygen, making it more susceptible to nucleophilic attack. The reaction does not yield iodobenzene or methanol in significant amounts under these reaction conditions. The process is essential in organic chemistry for the demethylation of aryl alkyl ethers.