Which major product is obtained by the addition of $1 \ mol$ of $HCl$ to $1,3$-butadiene at low temperature ($0^{\circ}C$ or below)?

Baeyer's reagent is ....

An alkene on ozonolysis gives methanal as one of the products. Its structure is

$CH_2 = CH_2 \xrightarrow[KOH / H_2O]{KMnO_4} X$. The product $X$ in the above reaction is:

What is the major product formed when $cis-2-butene$ reacts with $Br_2$ in $CCl_4$?

The reaction of $4$-methyloct$-1-$ene $(P, 2.52 \ g)$ with $HBr$ in the presence of $(C_6H_5CO_2)_2O_2$ gives two isomeric bromides in a $9:1$ ratio,with a combined yield of $50 \%$. Of these,the entire amount of the primary alkyl bromide was reacted with an appropriate amount of diethylamine followed by treatment with aqueous $K_2CO_3$ to give a non-ionic product $S$ in $100 \% $ yield. The mass (in $mg$) of $S$ obtained is. . . . . . . [Use molar mass (in $g \ mol^{-1}$) : $H=1, C=12, N=14, Br=80$]