Pressurised hydrogen gas is stored at 80°C in a 5 meter outer diameter spherical vessel having wall thickness of 5 cm. Molar concentration of H2at inner surface is 0.087 K mol/m3and outer surface is...

Pressurised hydrogen gas is stored at 80°C in a 5 meter outer diameter spherical vessel having wall thickness of 5 cm. Molar concentration of H2at inner surface is 0.087 K mol/m3and outer surface is zero. Find mass flow rate of H2by diffusion through spherical wall. Assume diffusion coefficient of H2through spherical wall is 1.2 x 10-12m2/s.