Question

In the dehydration of the above given primary alcohol, in the presence of 20% $H_{2}S{O}_4$ at ${85}^{o}C$ or 85% $H_{3}P{O}_4$ at ${80}^{o}C$ :

• A. the elimination mechanism is $E_1$ and direct as well as rearranged products are formed
• B. the elimination mechanism is $E_2$
• C. the elimination mechanism is $E_1$ and rearranged product alone is formed
• D. direct as well as rearranged products are formed

Answer 1

Answer: (B), (D)

The correct options are
B the elimination mechanism is $E_2$
D direct as well as rearranged products are formed

Since the alcohol is primary, the protonated alcohol loses $H_{2}O$ and $\beta$ hydrogen simultaneously forming alkene. It is $E_2$ elimination. Once the alkene is formed, it undergoes rearrangement in the presence of acid. Hence, rearranged product of alkene is also formed .