Estimate H f $298\backslash$deg for one of the following compounds as a liquid at $25\backslash$deg C$.($a$)$ Acetylene, $($b$)1,3-$Butadiene, $($c$)$ Ethylbenzene, $($d$)$ n$-$Hexane, $($e$)$ Styrene SOLVE FOR $($c$)$ Ethylbenzene