Neet Solved Paper 2013 Question 34

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

Options:

A) $ CH _3-CH _2-CH _2-CH _2-O-CH _3 $

B) $ CH _3-CH _2-\underset{\begin{smallmatrix} | \\ CH _3 \end{smallmatrix}}{\mathop{CH}},-O-CH _3 $

C) $ C{H_3}\text{-}\underset{\begin{smallmatrix} | \\ C{H_3} \end{smallmatrix}}{\overset{\begin{smallmatrix} C{H_3} \\ | \end{smallmatrix}}{\mathop{C}}},\text{-O-C}{H_3} $

D) $ C{H_3}\text{-}\underset{\begin{smallmatrix} | \\ C{H_3} \end{smallmatrix}}{\mathop{CH}},\text{-C}{H_2}\text{-O-C}{H_3} $

Show Answer

Answer:

Correct Answer: C

Solution:

  • The ether, which gives more stable carbonation, gives $ CH _3OH $ as one of the product with hot concentrated HI. The order of stability of carbonation is $ 3{}^\circ >2{}^\circ >1{}^\circ $ Thus, $ C{H_3}-\underset{\begin{smallmatrix} | \\ C{H_3} \end{smallmatrix}}{\overset{\begin{smallmatrix} C{H_3} \\ | \end{smallmatrix}}{\mathop{C}}},-OC{H_3} $ gives $ C{H_3}OH $ as one of the reaction. The reaction proceeds as $ {H_3}C-\underset{\begin{smallmatrix} | \\ C{H_3} \end{smallmatrix}}{\overset{\begin{smallmatrix} C{H_3} \\ | \end{smallmatrix}}{\mathop{C}}},-O-C{H_3}\text{+}{H^{+}} $