EXAMPLE PROBLEM :

Methane diffuses at steady state through a tube containing helium. At point $1$ the partial pressure of methane is $pA155$kPa and at point $2,0\mathrm{.}03m$ apart $P_{A2}=15$KPa. The total pressure is $101\mathrm{.}32$kPa, d the temperature is $298K.$ At this pressure and temperature, the value of diffusivity is $6\mathrm{.}75**{10}^{-5}\frac{m^2}{sec}.$

i$.$ calculate the flux of $C{H}_4$ at steady state for equimolar counter diffusion.

ii$.$ Calculate the partial pressure at a point $0\mathrm{.}02m$ apart from point $1.$