Explain the mechanism of dehydration of alcohols with a suitable example.

(N/A) $(i)$ Dehydration of alcohols occurs by heating them in the presence of protic acids like concentrated $H_2SO_4$ or $H_3PO_4$ or catalysts like anhydrous $ZnCl_2$ or alumina to form alkenes.
$CH_3CH_2OH \xrightarrow{\text{conc. } H_2SO_4} CH_2=CH_2 + H_2O$
$(ii)$ The dehydration of ethanol proceeds in three steps via a $\beta$-elimination mechanism.
Step-$1$: Protonation of alcohol. The proton $(H^+)$ from the acid attacks the $-OH$ group of the alcohol to form an oxonium ion $(-OH_2^+)$.
Step-$2$: Formation of carbocation. The $C-O$ bond breaks,releasing $H_2O$ and forming a carbocation. This is the slow and rate-determining step.
Step-$3$: Formation of ethene. $A$ $\beta$-proton is eliminated from the carbocation to form ethene. The $H^+$ used in Step-$1$ is released,regenerating the acid catalyst.