Which of the following alkenes is most easily formed by dehydrohalogenation of alkyl halides?

The product $(P)$ is:

Complete the following reactions:
$(i)$ $C_2H_4 + O_2 \rightarrow$
$(ii)$ $4Al + 3O_2 \rightarrow$

$^{14}CH_2=CH-CH_3 \xrightarrow[\text{or high temp}]{\text{low conc of } Br_2} (?)$
Product of the above reaction is

Identify the correct statements with respect to $cis/trans$-but$-2$-ene from the following:
$I$. $cis$-but$-2$-ene is more polar than $trans$-but$-2$-ene
$II$. Melting point of $cis$-but$-2$-ene is greater than that of $trans$-but$-2$-ene
$III$. Boiling point of $cis$-but$-2$-ene is greater than that of $trans$-but$-2$-ene
Correct answer is

Assertion : $1$-Butene on reaction with $HBr$ in the presence of a peroxide produces $1$-bromobutane.
Reason : It involves the formation of a primary radical.