The number of possible isomers of the compound with molecular formula $C_7H_8O$ is

Consider the following methods $:$
$I$: Hydration of olefins
$II$: Hydrolysis of alkyl halide
$III$: Reduction of carbonyl compounds
Which of these can be used to prepare alcohols ?

The major product in the following reaction sequence is:

What is $Z$ in the following sequence of reaction?
$Z$ $\xrightarrow{PCl_5} X$ $\xrightarrow{Alc. KOH} Y$ $\xrightarrow{dil. H_2SO_4} Z$

Match the following column:

Column-$I$ (Reaction)	Column-$II$ (Electrophile)
$A$. $C_6H_6 + CH_3Cl \xrightarrow{AlCl_3} C_6H_5CH_3$	$P$. $CO_2$
$B$. $C_6H_5OH + CO_2 \xrightarrow[H^+]{NaOH} \text{Salicylic acid}$	$Q$. $:CCl_2$
$C$. $C_6H_5OH + CHCl_3 \xrightarrow{KOH} \text{Salicylaldehyde}$	$R$. $\stackrel{+}{C}H_3$
$D$. $C_6H_6 + SO_3 \xrightarrow{H_2SO_4} C_6H_5SO_3H$	$S$. $\stackrel{+}{S}O_3H$
	$T$. $SO_3$

Cyclohexanol and phenol can be distinguished by