For example
Thus, the relative ease of dehydration of alcohols follows the
following order:
Tertiary
Secondary
Primary
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The mechanism of dehydration of ethanol involves the following steps:
Mechanism
Step 1: Formation of protonated alcohol Step 2: Formation of carbocation: It is the slowest step and hence, the
rate determining step of the reaction Step 3: Formation of ethene by elimination of a proton The acid used in step 1 is released in step 3