question_answer

Among the following ethers, which one will produce methyl alcohol on treatment with hot concentrated HI?

A)  \[C{{H}_{3}}-C{{H}_{2}}-C{{H}_{2}}-C{{H}_{2}}-O-C{{H}_{3}}\]

B)  \[C{{H}_{3}}-C{{H}_{2}}-\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{CH}}\,}}\,-O-C{{H}_{3}}\]

C)  \[C{{H}_{3}}-\underset{C{{H}_{3}}}{\overset{C{{H}_{3}}}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-O-C{{H}_{3}}\]

D)  \[C{{H}_{3}}-\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{CH}}\,}}\,-C{{H}_{2}}-O-C{{H}_{3}}\]

Correct Answer: C

Solution :

 The ether, which gives more stable carbocation, gives \[C{{H}_{3}}OH\]as one of the product with hot concentrated HI. The order of stability of carbocation is \[{{3}^{o}}>{{2}^{o}}>{{1}^{o}}\] Thus,\[C{{H}_{3}}-\underset{C{{H}_{3}}}{\overset{C{{H}_{3}}}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-OC{{H}_{3}}\] gives\[C{{H}_{3}}OH\] as one of the reaction. The reaction proceeds as \[{{H}_{3}}C-\underset{C{{H}_{3}}}{\overset{CH3}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-O-C{{H}_{3}}+{{H}^{+}}\]