Give the order of stability for different alkenes.

Predict the product$(s)$ obtained for the following reaction:
$3$-methylcyclopentene + $Br_2 / CCl_4 \rightarrow ?$

$HCl$ 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?

$Ph-CH_2-CH(Br)-CH_2-CH_3 \xrightarrow{NaNH_2} (A)$
Total number of elimination products are (includes stereoisomers):

$17 \, mg$ 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 $...........$.

An alkene $X$ on ozonolysis gives a mixture of $Propan-2-one$ and $methanal$. What is $X$?