a$)$ For questions $($i$)-($iv$)$ below, write the names and draw the structures of all molecules identified in your answers. Show all atoms and bonds.

$($i$)$ A stream of pure n$-$butane is fed to an FCC tower of a refinery. What products would be found in the outlet stream of this unit?

$($ii$)$ A C$3-$C$4$ hydrocarbon mixture is fed to an isomerisation tower. What products would be found in the outlet stream of this unit?

$($iii$)$ There is a proposal to feed hydrocarbon feedstock $($C$14-$C$16),$ which is to be used for diesel oil production, to an available isomerisation tower in the refinery What effect would this have on fuel quality and projected econemic consequences? Explain and justify your answer using no more than four $(4)$ sentences.

$(5)$

$($iv$)$ A newly discovered reservoir contains vast amounts of sour natural gas, with remarkably high content in olefins, and mercury presence. What market opportunities and processing issues arise for high profitability? Use no more than four $(4)$ sentences.

$(5)$