One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of $44 \ u$. The alkene is

Alkene $X$ $\xrightarrow[\Delta]{KMnO_4}$ (Butan$-2-$one) $+$ (Pentanoic acid). $X$ is

The correct order of rates of addition of $Br_2/\text{water}$ to the following alkenes is:
[$A$] $CH_2=CH_2$
[$B$] $CH_2=CH-NO_2$
[$C$] $CH_3-CH_2-CH=CH_2$
[$D$] $CH_3-CH=CH_2$

Rank the following alkenes in order of decreasing heats of hydrogenation (largest first):
$1$. $1-$butene
$2$. $2-$methyl$-2-$butene
$3$. trans$-2-$butene
$4$. cis$-2-$butene

Alkene $R-CH=CH_2$ reacts readily with $B_2H_6$ and the product on oxidation with alkaline hydrogen peroxide produces:

Among $HCl$,$HBr$,and $HI$,which reactant gives the Kharasch effect (peroxide effect) with an alkene?