Question

Which of the ethers will produce methyl alcohol on treatment with hot concentrated $\mathrm{HI}$?

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The correct option is C

The explanation for correct options-

Methyl tert-butyl ether:

• Methyl tertiary-butyl ether, also known as methyl tert-butyl ether is an organic compound with a structural formula${\left({\mathrm{CH}}_3\right)}_3{\mathrm{COCH}}_3$.
• Following the nucleophilic substitution process, ether undergoes a reaction with a strong Hydriodic acid $\left(\mathrm{HI}\right)$ which results in the breaking of the ether $\mathrm{C}-\mathrm{O}$ bond.
• The chemical reaction can be depicted as:
• 

• The degree of the alkyl group present in the ether also affects the cleavage.
• with primary and secondary alkyl ethers having reduced steric resistance.
• So, the ${\mathrm{S}}_{\mathrm{N}}2$ mechanism is demonstrated.
• In contrast, the tertiary alkyl ether follows the ${\mathrm{S}}_{\mathrm{N}}1$ process through the creation of the stable carbocation intermediate due to steric hindrance.

The explanation for incorrect options-

Option (A)-

Through the $S_{N}2$ mechanism, having $1^{\circ }$alkyl group, on reaction with HI, it forms butanol and methyl iodide.

Option (B)-

This compound, it is having a $2^{\circ }$alkyl group, and in the reaction, it forms methyl iodide and isobutyl alcohol.

Option (D)-

In this compound on reaction with $\mathrm{HI}$, it forms 2-methyl propanol and methyl iodide.

Therefore, option (C) is the correct answer.