It is desired to calculate the rate of diffusion of Coz gas in air at steady state through a loosely packed bed of sand at $276$K and a total pressure of $1\mathrm{.}013*18$ Pa$.$ The bed depth is $1\mathrm{.}25$ m and the void fraction & is $0\mathrm{.}3.$ The partial pressure of Cor at the top of the bed is $2\mathrm{.}026*10$ Pa and o la at the bottom. Use a $7$ of $1\mathrm{.}87.$