Write the mechanism of the reaction of HI with methoxybenzene.

Explanation

In case of alkyl aryl ethers, the products are always phenol and an alkyl halide because due to resonance `C_(6)H_(5)-O` bond has partial double bond character. The mechanism is given below.
Mechanism Protonation of anisole gives methylphenyl oxonium ion.
`C_(6)H_(5)-underset(..)overset(..)(O)CH_(3)+H^(+) rarr C_(6)H_(5)-underset(H)underset(|)overset(+)(O):-CH_(3)`
In this ion, the bond between `O-CH_(3)` is weaker than the bond between `O-C_(6)H_(5)` which has partial double bond character. The partial double bond character is due to the resonance between the lone pair of electrons on the O atom and the `sp^(2)` hybridised carbon atom of the phenyl group. Therefore, attack by `I^(-)` ion exclusively breaks the weaker `O-CH_(3)` bond forming methyl iodide and phenol.