Predict the major product of acid-catalyzed dehydration of:
$(i)$ $1$-methylcyclohexanol
$(ii)$ butan-$1$-ol

(N/A) $(i)$ Acid-catalyzed dehydration of $1$-methylcyclohexanol proceeds via the formation of a tertiary carbocation. The loss of a proton from the adjacent carbon leads to the formation of $1$-methylcyclohexene as the major product.
$(ii)$ Acid-catalyzed dehydration of butan-$1$-ol proceeds via the formation of a primary carbocation,which undergoes rearrangement to a more stable secondary carbocation. Subsequent loss of a proton yields but-$2$-ene as the major product.
Reaction for $(i)$:
$1$-methylcyclohexanol $\xrightarrow{H^+}$ $1$-methylcyclohexene $+ H_2O$
Reaction for $(ii)$:
$CH_3CH_2CH_2CH_2OH \xrightarrow{H^+} CH_3CH=CHCH_3$ (but-$2$-ene,major product) $+ H_2O$