Compare the time it takes for $1$ mole of ethanol to diffuse through:

a$)$ a film of stagnant air

b$)$ a stagnant film of liquid water.

If in each of these cases the thickness of the film is $3$mm and the initial and final concentrations are $0\mathrm{.}01$ mol$/$m$3$ and zero, respectively, the pressure and temperature of the system are $1\mathrm{.}013$x$10^5$ Pa and $283$ K