Give the major products that are formed by heating each of the following ethers with $HI$.
$(i)$ $CH_3-CH_2-CH(CH_3)-CH_2-O-CH_2-CH_3$
$(ii)$ $CH_3-CH_2-CH_2-O-C(CH_3)_2-CH_2-CH_3$
$(iii)$ $C_6H_5-CH_2-O-C_6H_5$

(N/A) $(i)$ The reaction follows $S_N2$ mechanism because the alkyl groups are primary. The smaller alkyl group forms the alkyl iodide. Products: $CH_3-CH_2-CH(CH_3)-CH_2OH + CH_3CH_2I$.
$(ii)$ The reaction follows $S_N1$ mechanism because the ether contains a tertiary alkyl group. The tertiary carbocation is more stable. Products: $CH_3CH_2CH_2OH + CH_3CH_2-C(CH_3)_2I$.
$(iii)$ The cleavage occurs at the $C-O$ bond where the benzyl carbocation is formed,which is resonance stabilized. Products: $C_6H_5CH_2I + C_6H_5OH$.