Q$4)$ PACKed BEd Pure water flows at $2$l$//$hr through a packed bed of $6\mathrm{.}5$mm benzoic acid spheres. The total area of the spheres is $130$cm$^(2).$ If the concentration of benzoic acid in the outlet stream is $3$mol$//$m$^(3)$ and the system temperature is $38^($@$)$C$,$ what is the mass transfer coefficient?roelifient?