Butane can be prepared from butene by reaction with........

Major product '$P$' formed in the following reaction is:-

Ozonolysis of an alkene produces only one dicarbonyl compound. The structure of the alkene is:

Identify the major products $X$ and $Y$ in the following reactions:
$(i)$ $C_6H_5-CH=CH_2 + HBr \rightarrow X$
(ii) $C_6H_5-CH_2-CH=CH_2 + HBr \xrightarrow{\text{Peroxide}} Y$

The reaction of $CH_3-CH=C(CH_3)-CH=CH_2$ with $(1) \ O_3$ followed by $(2) \ H_2O, Zn$ gives which products?

$HCl$ 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?