Addition of $Br_2$ to $cis$-$2$-butene would give a product which is

An organic compound $X$ with molecular formula $C_{11}H_{14}$ gives an optically active compound on hydrogenation. Upon ozonolysis,$X$ produces a mixture of compounds $P$ and $Q$. Compound $P$ gives a yellow precipitate when treated with $I_{2}$ and $NaOH$ but does not reduce Tollen's reagent. Compound $Q$ does not give any yellow precipitate with $I_{2}$ and $NaOH$ but gives Fehling's test. The compound $X$ is:

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

Consider the following sequence of reactions: $CH_3-CH=CH_2$ $\xrightarrow[700\,K]{Cl_2} A$ $\xrightarrow[420\,K, 12\,atm]{Na_2CO_3} B$ $\xrightarrow[(ii) NaOH]{(i) HOCl} C$. Compound $C$ is:

Which of the following products is not formed during the reaction: $CH_3-CH(CH_3)-CH=CH_2 \xrightarrow{Br_2/aq. NaCl}$?

Addition of $HBr$ to propene yields $2$-bromopropane,while in the presence of benzoyl peroxide,the same reaction yields $1$-bromopropane. Explain and give mechanism.