$\mathrm{HBr}$ reacts with $\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{OCH}_{3}$ under anhydrous conditions at room temperature to give

• A

  $\mathrm{BrCH}_{2}-\mathrm{CH}_{2}-\mathrm{OCH}_{3}$
• Correct answer
  B

  $\mathrm{H}_{3} \mathrm{C}-\mathrm{CHBr}-\mathrm{OCH}_{3}$
• C

  $\mathrm{CH}_{3} \mathrm{CHO}$ and $\mathrm{CH}_{3} \mathrm{Br}$
• D

  $\mathrm{BrCH}_{2} \mathrm{CHO}$ and $\mathrm{CH}_{3} \mathrm{OH}$

Solution

Methyl vinyl ether under anhydrous condition at room temperature undergoes addition reaction.

Hence, the correct answer is option: 'B'.