3. In a steelmaking process using molten pig iron that contains carbon, a spray of molten iron particles containing 4.0 wt% carbon falls through a pure-oxygen atmosphere. The carbon diffuses gas stream at point 1 to a catalyst surface at point 2 and reacts instantaneously and irreversibly as follows: 2AB Gas B diffuses back to the gas stream. Derive the final equation for NA at constant pressure P and steady state in terms of partial pressures, diffusivity DAB