Which of the following is obtained as a product when ethylene reacts with oxygen in the presence of $Pd / Al_2O_3$?

$HCl$ does not show the peroxide effect because the reaction mechanism involves the following steps:
$CH_3-CH=CH_2 + \dot{X} \to CH_3-\dot{C}H-CH_2X$ $(I)$
$CH_3-\dot{C}H-CH_2X + HX \to CH_3-CH_2-CH_2X + \dot{X}$ $(II)$
Why does $HCl$ fail to undergo this reaction?

$17 \, mg$ of a hydrocarbon ($M$.$F$. $C_{10}H_{16}$) takes up $8.40 \, mL$ of $H_2$ gas measured at $0^{\circ}C$ and $760 \, mm$ of $Hg$. Ozonolysis of the same hydrocarbon yields acetone,formaldehyde,and a compound with the structure $CH_3-CO-CH_2-CH_2-CHO$. The number of double bonds present in the hydrocarbon is $...........$.

$2-$methylbut$-2-$ene $\xrightarrow[\text{(ii) } Zn / H_2 O]{\text{(i) } O_3}$ products here are . . . . . . .

An optically active alkene having molecular formula $C_8H_{16}$ gives acetone as one of the products on ozonolysis. The structure of the alkene is:

Identify the products $A$ and $B$ formed in the following reaction:
$CH_3 - CH_2 - CH = CH - CH_3 + HCl \to A + B$