Identify the major product $X$ in the following reaction:
$C_6H_5-CH_2-CH=CH_2 \xrightarrow{HBr, R_2O_2} X$

Give the increasing order of stability for the following alkenes based on their heat of hydrogenation $(\Delta H^o)$:
$(I) (CH_3)_2C = C(CH_3)_2$
$(II) CH_3CH_2CH_2CH = CH_2$
$(III) (CH_3)_2C = CHCH_3$
$(IV) CH_3CH_2C(CH_3) = CH_2$

In hydroboration-oxidation reaction $:-$
$I$. Syn addition takes place
$II$. Reaction proceeds through the formation of a cyclic transition state
$III$. Vicinal diol is obtained as a product
$IV$. Anti-addition takes place and Anti-Markovnikov rule is followed
Which of the following statement$(s)$ is/are correct $:-$

Suppose the following reaction,the major product will be:

$CH_3-CH_2-CH_2-CH_2-C(CH_3)_2-CH_2-OH \xrightarrow[\Delta]{H^{+}} (A) \text{ (major)}$. Product $(A)$ is

In which of the following,addition of $HBr$ does not take place against Markownikoff's rule,or for which is the Anti-Markownikoff addition of $HBr$ not observed?