1. Pressurized helium gas is stored at 300K and 4 bar in a 0.2 m inside diameter spherical container made of steel. The shell of the container is 2 mm thick. The solubility of helium in the steel is 0.45 x 10 kmol/ml.bar. The concentration of helium in the steel at the outer surface is negligible. (a) Determine the molar flow rate of helium by diffusion through the steel container. Given that He-Steel = 0.4 x 10"m/s. (b) To obtain the concentration profile of helium for the above problem, write the final differential equation and the corresponding boundary conditions assuming 1-D, steady state and without reaction conditions. (No need to solve the differential equation)