The hottest region of the Bunsen flame shown in the figure below is:

"$P$" is a hydrocarbon with the molecular formula $C_8H_{14}$. On ozonolysis,"$P$" forms "$Q$". "$Q$" on treatment with alkali under reflux conditions produces "$R$",which on treatment with $I_2/NaOH$ gives a yellow precipitate. Acidification of the solution gives "$S$". The structure of "$S$" is given below:
(Structure $S$: $1-$methyl$-2-$oxocyclopentanecarboxylic acid derivative or similar cyclic structure as per common reaction pathways).
The correct structure of "$P$" is:

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

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

The major product $A$ is:

What is $Z$ in the following reaction sequence ?
$C_3H_6$ $\xrightarrow[CCl_4]{Br_2} \underset{\text{(colourless)}}{X}$ $\xrightarrow[\text{(ii) } NaNH_2, \Delta]{\text{(i) } KOH / \text{alcohol}} Y$ $\xrightarrow[\substack{Hg^{2+}, H^{+} \\ 333 \ K}]{H_2O} Z$