Which of the following compounds has the minimum heat of hydrogenation?

$A$ hydrocarbon has a molecular mass of $84 \ g/mol$. What is the number of its structural chain isomers?

Addition of $HCl$ to propene in the presence of peroxides gives:

Suppose the following reaction sequence: $CH \equiv CH$ $\xrightarrow[\text{excess}]{NaNH_2 / \text{liq. } NH_3} A$ $\xrightarrow{2 CH_3 - I} B$ $\xrightarrow{H_2 / Pd - BaSO_4, \text{ quinoline}} C$ and $C$ $\xrightarrow{H_2 / Pd - BaSO_4, \text{ quinoline}}$ $\xrightarrow{NaNH_2 / \text{liq. } NH_3} D$. How are $C$ and $D$ related?

Ethylene reacts with ..... to form ethylene chlorohydrin.

Identify products $[A]$,$[B]$,and $[C]$ in the following reaction sequence:
$CH_3-C \equiv CH$ $\xrightarrow{H_2, Pd/C} [A]$ $\xrightarrow[(ii) Zn, H_2O]{(i) O_3} [B] + [C]$