Benzene diffusion contaminating soil ( 6pts ) Benzene is diffusing through water-saturated soil, contaminating it. At 293K, benzene has solubility in water of 23mole/m3 and effective diffusivity of 109m2/sec and density of 0.88 g/cm3. If initially there is no benzene dissolved in the water-saturated soil layer, (a) Calculate the concentration of dissolved benzene at a position of 10cm into the water-saturated soil 100 hours after the spill. (b) How long will it take for the concentration of benzene at 0.5m depth to reach 1g/m3, the toxicity limit? You may assume that water-saturated soil approximates the property of a homogeneous substance