A rectangular section of a porous solid 0.5 in thick is submerged in 100% ethanol. The voids of solid compose 50% of its

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A Rectangular Section Of A Porous Solid 0 5 In Thick Is Submerged In 100 Ethanol The Voids Of Solid Compose 50 Of Its 1 (148.31 KiB) Viewed 16 times

A rectangular section of a porous solid 0.5 in thick is submerged in 100% ethanol. The voids of solid compose 50% of its volume. The solid is removed from the ethanol after thorough soaking and placed in an agitated tank of water at 80°F. Only molecular diffusion occurs in the pores, and the diffusivity inside the pores is approximately one tenth of its value out-side the solid. What length of time is required for the mass fraction of ethanol at the center of the solid to drop to 0.008? Assume the concentration of ethanol in the water phase is always zero.