Product '$A$' and '$B$' are respectively:
$CH_3-C(CH_3)=CH-C_6H_5 \xrightarrow{HBr/Peroxide} A$
$CH_3-C(CH_3)=CH-C_6H_5 \xrightarrow{HBr} B$

$CH_3-CH=CH-CH_3 \xrightarrow[R_2O_2, \Delta]{HBr} \text{ (Anti-Markownikoff's addition)}$
Comment on the optical activity of the products.

An organic compound $(A)$ on ozonolysis followed by treatment with zinc dust and water gives product $(P)$,which can be used to preserve biological specimens. Identify $(A)$.

Identify the type of the given reactions:
$(a) \ CH_3CH_2OH \xrightarrow[\Delta]{\text{Conc. } H_2SO_4} CH_2 = CH_2 + H_2O$
$(b) \ CH_2BrCH_2Br + Zn \xrightarrow{\Delta} CH_2 = CH_2 + ZnBr_2$
$(c) \ CH_3CHBr - CH_2Br + Zn \xrightarrow{\Delta} CH_3CH = CH_2 + ZnBr_2$
$(d) \ RC \equiv CR' + H_2 \xrightarrow{Na, \text{liquid } NH_3} RCH = CHR'$
$(e) \ CH_3CH_2Cl + KOH \xrightarrow{\text{ethanol, } KOH} CH_2 = CH_2 + KCl + H_2O$

Identify $Z$ in the following series: $C_2H_5I$ $\xrightarrow{Alco. KOH} X$ $\xrightarrow{Br_2} Y$ $\xrightarrow{KCN} Z$

Indicate the organic structure for the product expected when $2-$methylpropene is heated with acetyl chloride in the presence of anhydrous zinc chloride.