An alkene $(X)$ on ozonolysis gives propanal and ethanal. What is $X$?

The bond length of the $C-H$ bond in ethene is ...... $pm$.

What is the major product of the following reaction?
$3$-methylenecyclohexan-$1$-ol + $H_2$ ($1$ eq.) / $Ni$,$\Delta$ $\rightarrow$ ?

The number of $sp^3$ hybridized carbon atoms in cyclohexene is

Two isomers $A$ and $B$ with molecular formula $C_4H_8$ give different products on oxidation with $KMnO_4$ in acidic medium. Isomer $A$ on reaction with $KMnO_4 / H^{+}$ results in effervescence of a gas and gives a ketone. The compound $A$ is ...... .

Which of the following structures represents $1,3\text{-butadiene}$?