In which one of the following conversions is phosphorus pentachloride $(PCl_5)$ used as a reagent?

Read the following statements carefully :
$(A)$ $A$ secondary alcohol on oxidation gives a ketone
$(B)$ Ethanol reacts with conc. $H_2SO_4$ at $180\,^{\circ}C$ to yield ethylene
$(C)$ Methanol reacts with iodine and sodium hydroxide to give a yellow precipitate of iodoform
$(D)$ Hydrogen gas is liberated when sodium is added to alcohol. Select the correct statements from the above set:

Write the chemical reactions for the following conversions:
$1.$ Propan$-2-$ol to $2-$methylbutan$-2-$ol
$2.$ Benzenesulphonic acid to benzoquinone

Consider the following reaction:
Which response contains all the correct statements about this process?
$1.$ Dehydration
$2.$ $E_2$ mechanism
$3.$ Carbon skeleton migration
$4.$ Most stable alkene will form
$5.$ Single-step reaction

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

Match the items of column $-I$ with the items of column $-II$.

Column $-I$	Column $-II$
$(A)$ Methanol	$(1)$ Conversion of phenol to $o-$hydroxybenzoic acid
$(B)$ Kolbe's reaction	$(2)$ Ethyl alcohol
$(C)$ Williamson's synthesis	$(3)$ Conversion of phenol to salicylaldehyde
$(D)$ Conversion of $2^o-$ alcohol to ketone	$(4)$ Wood spirit
$(E)$ Reimer-Tiemann reaction	$(5)$ Heated copper at $573 \ K$
$(F)$ Fermentation	$(6)$ Reaction of alkyl halide with sodium alkoxide