Olefins can be hydrogenated by

What is the product formed when ethylene reacts with $1\%$ cold alkaline $KMnO_4$?

The major product of the reaction is:

$CH_3-CH=CH_2$ $\xrightarrow{Br_2, hv (\text{low conc.})} \dots$ $\xrightarrow{Mg, \text{Dry ether}} \dots$ $\xrightarrow{CH_3-CO-CH_3, NH_4Cl} \dots$ $\xrightarrow{H^{+}, \Delta} (X)$. The end product $(X)$ of the above reaction is:

Identify the reagent$(s)$ $A$ and condition$(s)$ for the reaction shown in the image:

Identify $Z$ in the following series: $C_2H_5I$ $\xrightarrow{Alco. KOH} X$ $\xrightarrow{Br_2} Y$ $\xrightarrow{KCN} Z$