The heating of phenyl ethyl ether with HI, gives Phenol (C6H5OH)
》C6H5-O-CH3+HI=(del above the Arrow)=C6H5OH+CH3-I.
•A molecule of HI is added to ether. I atom is added to CH3- group and H- atom is attached to O atom.Here,Ph-O bond is not broken as neucleophilic aromatic substitution requires drastic condition.

The heating of phenyl-methyl ethers (also known as aryl-methyl ethers) with HI (hydrogen iodide) leads to the formation of iodobenzene as the major product. This reaction is known as the cleavage of aryl-methyl ethers.

Explanation:

Cleavage of Aryl-Methyl Ethers:
The cleavage of aryl-methyl ethers is a common reaction in organic chemistry, where the aryl-methyl ether is converted into its corresponding aryl halide. In this reaction, the oxygen atom of the ether is replaced by a halogen atom (in this case, iodine).

Reaction Mechanism:
The reaction proceeds through a nucleophilic substitution mechanism. Here is the step-by-step explanation of the reaction:

1. Formation of the protonated ether:
Heating the phenyl-methyl ether with HI leads to the protonation of the ether oxygen by the HI acid. This forms a protonated ether intermediate.

2. Nucleophilic attack of iodide ion:
The protonated ether intermediate undergoes nucleophilic attack by the iodide ion (I-) present in excess due to the presence of HI. The iodide ion attacks the carbon atom attached to the aryl group, breaking the carbon-oxygen bond.

3. Formation of the carbocation:
The nucleophilic attack by iodide ion leads to the formation of a carbocation intermediate. The iodide ion takes the place of the oxygen, leaving a positive charge on the carbon atom.

4. Rearrangement (if applicable):
If there is a possibility of carbocation rearrangement, it may occur at this stage to form a more stable carbocation intermediate.

5. Deprotonation and formation of the aryl iodide:
The carbocation intermediate is then deprotonated by the iodide ion, resulting in the formation of the aryl iodide as the final product. The iodide ion acts as a base, abstracting the proton from the carbocation to restore charge neutrality.

Conclusion:
In conclusion, when phenyl-methyl ethers are heated with HI, the reaction proceeds via a nucleophilic substitution mechanism, resulting in the formation of iodobenzene as the major product. This reaction is useful for the synthesis of aryl halides, which are important intermediates in various organic synthesis processes.