Question -
Answer -
The mechanism of acid dehydration of ethanol to yieldethene involves the following three steps:
Step 1:
Protonation of ethanol to form ethyl oxonium ion:
Step 2:
Formation of carbocation (rate determining step):
Step 3:
Elimination of a proton to form ethene:
The acid consumed in step 1 is released in Step 3. Afterthe formation of ethene, it is removed to shift the equilibrium in a forwarddirection.