Alkyl halides react with dialkyl copper reagents (Gilman reagents) to give:

Identify the correct order of reactivity for the reaction with alcoholic $KOH$ for the following compounds:
$(a)$ $2$-bromo-$2,3$-dimethylbutane
$(b)$ $2$-chlorobutane
$(c)$ $2$-bromobutane
$(d)$ $1$-bromopropane

The decreasing order of reactivity towards dehydrohalogenation $(E_1)$ reaction of the following compounds is:
$(A)$ $CH_3CH_2CH_2CH_2Cl$
$(B)$ $CH_2=CHCH_2CH_2Cl$
$(C)$ $CH_3CH_2CHClCH_3$
$(D)$ $CH_2=CHCHClCH_3$

By passing excess $Cl_{2(g)}$ in boiling toluene,which one of the following compounds is exclusively formed?

What are $X$ and $Y$ in the following reaction sequence?

Identify the correct reactivity order for the $S_N2$ reaction for the following compounds:
$(i)$ $CH_2=CH-Cl$
(ii) $CH_2=CH-CH_2-Cl$
(iii) $N\equiv C-CH_2-CH_2-Cl$