12: Methane gas (CH) is diffusing at constant rate through a layer of stagnant air 1mm thick. Conditions are fixed so that the mole fraction of methane in stagnant air contains 50%. The methane gas diffusing to the other boundary is quickly absorbed and the concentration is negligible (PA2=0.0). The temperature is 295K and the pressure atmosphere (101.3 KN/m?). Molar volume of Methane and air is 24.42 and 20.1 respectively. molecular weights of Methane and Air are 16.043 and 29Kg/Kmol respectively. 1. Calculate the diffusivity of Methane gas through the air? 2. Calculate the rate of diffusion of Methane gas through the air?(30 Marks