Show the $\beta$-elimination reactions for the following alcohols:
$(i)$ Propyl alcohol
$(ii)$ Isopropyl alcohol
$(iii)$ Cyclohexanol
$(iv)$ Tertiary-butyl alcohol.

(N/A) When alcohols are treated with concentrated $H_{2}SO_{4}$,they undergo dehydration to form alkenes,a process known as $\beta$-elimination reaction.
$(i)$ $CH_{3}CH_{2}CH_{2}OH \xrightarrow[\Delta, 443 \ K]{Conc. \ H_{2}SO_{4}} CH_{3}CH=CH_{2} + H_{2}O$ (Propene)
$(ii)$ $CH_{3}CH(OH)CH_{3} \xrightarrow[438-443 \ K]{H_{2}SO_{4}} CH_{3}CH=CH_{2} + H_{2}O$ (Propene)
$(iii)$ $C_{6}H_{11}OH \xrightarrow[373-383 \ K]{H_{2}SO_{4}/H_{3}PO_{4}} C_{6}H_{10} + H_{2}O$ (Cyclohexene)
$(iv)$ $(CH_{3})_{3}COH \xrightarrow[\Delta, 360 \ K]{H_{2}SO_{4}} CH_{3}-C(CH_{3})=CH_{2} + H_{2}O$ ($2$-Methylpropene)