In the reaction,$H_2C = CH_2 \xrightarrow{\text{cold alkaline } KMnO_4} (A)$. Product $A$ is :

For the given reaction sequence,identify $C$ and $D$:
$3\text{-methylbut-1-ene}$ $\xrightarrow[(ii) NaBH_4]{(i) Hg(OAc)_2/H_2O} A$ $\xrightarrow{H^\oplus/\Delta} B$ $\xrightarrow{O_3/Zn/H_2O} C + D$

Which of the following alkenes yield $3-$bromo$-3-$methylpentane as the major product upon addition of $HBr$?
$(I)$ $3-$methylpent$-2-$ene
$(II)$ $3-$methylpent$-2-$ene (isomer)
$(III)$ $3-$ethylpent$-1-$ene
$(IV)$ $3-$methylpent$-1-$ene

Which of the following reactions proceeds via a secondary free radical?

An organic compound $(A)$ on ozonolysis followed by treatment with zinc dust and water gives product $(P)$,which can be used to preserve biological specimens. Identify $(A)$.

Ozonolysis of which olefin yields $CH_3CH_2CHO$ and $CH_3CHO$?