$Cl_2$ reacts with $CS_2$ in the presence of an $I_2$ catalyst to form:

The products $A$ and $B$ obtained in the following reactions,respectively,are
$3 ROH + PCl_3 \rightarrow 3 RCl + A$
$ROH + PCl_5 \rightarrow RCl + HCl + B$

The synthesis of alkyl fluorides is best accomplished by

Which among the following reactions is used for the preparation of alkyl fluorides?

Which one of the following reactions would be the best for the formation of $2-$bromobutane?
$(1)$ $CH_3CH=CHCH_2CH_3$ $\xrightarrow{HBr}$
$(2)$ $CH_3CH_2CH=CH_2$ $\xrightarrow{HBr}$
$(3)$ $CH_3CH=CHCH_3$ $\xrightarrow{Br_2}$
$(4)$ $CH_3CH_2CH=CH_2$ $\xrightarrow[Peroxide]{HBr}$

$Ph-CH(OH)-CH_3 \xrightarrow{SOCl_2}$ major product