Write the products of the addition reaction $ >C = C < + XY \to $

An optically active alkene having molecular formula $C_8H_{16}$ gives acetone as one of the products on ozonolysis. The structure of the alkene is:

Which of the following gases decolourises $KMnO_4$ solution but does not give a precipitate with ammoniacal cuprous chloride?

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 $g \ mol^{-1}$) : $H=1, C=12, N=14, Br=80$]

The name of the product obtained by the addition of $HI$ to propene in the presence of a peroxide catalyst is:

Explain the preparation of alkene from alkyl halide via dehydrohalogenation in detail.