The catalyst used for the isomerisation of $n$-alkanes to branched chain alkanes is

What are $X$ and $Y$ respectively, in the following set of reactions?

$$ \begin{aligned} &\text { Consider the following reaction sequence }\\ &\text { Vinyl benzene } \xrightarrow[\Delta]{\mathrm{KMnO}_4+\mathrm{KOH}} X \xrightarrow[\Delta]{\mathrm{NaOH}+\mathrm{CaO}} Y \end{aligned} $$

$' Y$ ' can also be formed from

When ethyl bromide and $n$-propyl bromide are allowed to react with Na metal in dry ether, the number of different alkanes formed is