Methoxybenzene on treatment with HI produces phenol and methyl iodide. This is due the more stable aryl oxygen bond. Here. methyl phenyl oxonium ion is formed by the protonation of ether. The bond between $\mathrm{O}-\mathrm{CH}_{3}$ is weaker than the bond between $\mathrm{O}-\mathrm{C}_{6} \mathrm{H}_{5}$ because the carbon of phenyl group is $s p^{2}$ -hybridised and there is a partial double bond character. Thus, the reaction yields phenol and alkyl halide.