Identify the most suitable reagents $(I)$ and $(II)$ for the following sequence of reactions:

For the following reactions:
$CH_{3}CH_{2}CH_{2}Br + Z^{-} \xrightarrow[substitution]{k_s} CH_{3}CH_{2}CH_{2}Z + Br^{-}$
$CH_{3}CH_{2}CH_{2}Br + Z^{-} \xrightarrow[elimination]{k_e} CH_{3}CH=CH_{2} + HZ + Br^{-}$
where
$Z^{-} = CH_{3}CH_{2}O^{-} (A)$ or $(CH_{3})_{3}CO^{-} (B)$
$k_s$ and $k_e$ are,respectively,the rate constants for the substitution and elimination,and $\mu = \frac{k_s}{k_e}$,the correct option is:

Predict the order of reactivity of the following four isomers towards $S_{N}2$ reaction.
$(I)$ $CH_{3}CH_{2}CH_{2}CH_{2}Cl$
$(II)$ $CH_{3}CH_{2}CH(Cl)CH_{3}$
$(III)$ $(CH_{3})_{2}CHCH_{2}Cl$
$(IV)$ $(CH_{3})_{3}CCl$

An alcoholic solution of $KOH$ is a specific reagent for which of the following reactions?

Which among the following is $NOT$ a feature of $S_{N}2$ mechanism?

The reaction involving the coupling of an aryl halide and an alkyl halide in the presence of sodium metal and dry ether is known as: