Beaker

As shown in Figure, an open beaker, $6cm$ in height, is filled with liquid benzene at $25C$ to within $0\mathrm{.}5cm$ of the top. A gentle breeze of dry air at $25C$ and $1$atm is blown by a fan across the mouth of the beaker so that evaporated benzene is carried away by convection after it transfers through a stagnant air layer in the beaker. The vapor pressure of benzene at $25C$ is $0\mathrm{.}131$atm. The mutual diffusion coefficient for benzene in air at $25C$ and $1$atm is $0\mathrm{.}0905cm\frac{2}{s}.$ Compute:

$($a$)$ The initial rate of evaporation of benzene as a molar flux in $mo\frac{l}{c}m2-s$

$($b$)$ The initial mole$-$fraction profiles in the stagnant air layer

$($c$)$ The initial fractions of the mass$-$transfer fluxes due to molecular diffusion

$($d$)$ The initial diffusion velocities, and the species velocities $($relative to stationary coordinates$)$ in the stagnant layer

$($e$)$ The time in hours for the benzene level in the beaker to drop $2cm$ from the initial level, if the specific gravity of liquid benzene is $0\mathrm{.}874.$ Neglect the accumulation of benzene and air in the stagnant layer as it increases in height