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 O−CH3 is weaker than the bond between O−C6H5 because the carbon of phenyl group is sp2-hybridised and there is a partial double bond character. Thus, the reaction yields phenol and alkyl halide.
