The order of reactivity of $C_2H_6$,$C_2H_4$,and $C_2H_2$ is.......

Match the following reactions in List-$I$ with their products in List-$II$:

List-$I$	List-$II$
$A$. The reaction of $1,6$-dibromohexane with $Zn$.	$i$. $H_3C-C \equiv CH$
$B$. Reaction of ethanol with concentrated $H_2SO_4$ at $443 \ K$.	$ii$. $H_2C=CH_2$
$C$. Major product in the reaction of propene with $HBr$ in the presence of benzoyl peroxide.	$iii$. $CH_3-CH_2-CH_2-Br$
$D$. The reaction of $1,1$-dibromopropane with $NaNH_2$ at $433 \ K$.	$iv$. Cyclohexane

Product $(B)$ of the reaction is

$Ph-CH_2-C\equiv N$ $\xrightarrow[THF]{LDA}$ $\xrightarrow{CH_3I} 71\%;$ The end product of this reaction will be:

What are $X$ and $Y$ respectively in the following sets of reactions?
$I. \ CH_3CH_2CH_2OH \xrightarrow{PBr_3} X$
$II. \ CH_3CH=CH_2 \xrightarrow{HBr, (C_6H_5COO)_2} Y \text{ (major)}$

The octane number can be improved by $...............$.