Notes

Reaction with Halogen Acids in Ethers…

The reactivity order of halogen acids for this reaction are HI>H-Br>H-Cl.
As size of halide ion increases in the order Cl^– < Br^– I^– and hence, nucleophilicity increases.
In case of asymmetrical ethers, the alkyl halide is always formed from the smaller alkyl group. If alkyl group is (3°), halogen gets attached with it. If one R group is phenyl and other is alkyl group, the cleavage of C-O bond produces phenol and alkyl halide.