Question

$1^{\circ }$ alcohols preferably undergo dehydration in presence of $A{l}_2{O}_3$:

• A. $E_1$
• B. $E_2$
• C. $S_{N}1$
• D. $S_{N}2$

Answer 1

The correct option is B $E_2$

Primary alcohol dehydrates through the $E_2$ mechanism

Oxygen donates two electrons to a proton from sulfuric acid $H_{2}S{O}_4$,

forming an alkyloxonium ion.

Then the nucleophile $H_{2}S{O}_4$ back-side attacks one adjacent hydrogen and the alkyloxonium ion leaves in a concerted process, making a double bond.