One mole of $CH X_{3} - O - CH X_{2} CH X_{2} - O - C X_{6} H X_{5}$ (1-methoxy-2-phenoxyethane) is heated with a large excess of hot, concentrated $HI$ . Assume that every aliphatic ether C-O bond is cleaved, that every alcohol formed is converted into the alkyl iodide, and that the aryl C-O bond and the benzene ring are untouched. How many moles of $HI$ are consumed? (nearest integer)

Numerical answer type, tolerance 0.5.

Answer: 3

Cleavage of

C X_{6} H X_{5} - O - CH X_{2}

uses 1 HI and gives phenol plus

ICH X_{2} CH X_{2} OCH X_{3}

. Cleavage of the remaining

CH X_{3} - O - CH X_{2}

link uses 1 HI to give

CH X_{3} I

and

HOCH X_{2} CH X_{2} I

, and converting this alcohol to

ICH X_{2} CH X_{2} I

uses 1 more HI. Total = 1 + 1 + 1 = 3 mol; check: iodine atoms in

CH X_{3} I

and

ICH X_{2} CH X_{2} I

= 3.