Estimate the steady-state flux of atomic hydrogen at 25 °c through a steel vessel of wall thickness 4 mm given that its inside surface is kept saturated with hydrogen at a concentration of 4.2 moles m ; the outside surface is exposed to the atmosphere. the diffusivity of hydrogen in a-iron is d. = 0.1 mm ? s? , q = 13.4 kj mol? . if the vessel contains 20 moles of hydrogen, estimate the hours taken to dissipate all of the hydrogen given that the vessel has a surface area of 2m². comment on why it is possible to store hydrogen gas in iron cylinders for much longer periods. how does dissolved hydrogen affect the mechanical properties of a-iron?