The experiment shown below is used to estimate mass transfer coefficients. In the present experiment, two portions of the inside of the tube are coated with naphthalene, a volatile solid. The tube is maintained at 100°C and 1.0 atm total system pressure. At 100°C, the sublimation vapor pressure of solid naphthalene is 1.0 mmHg. The inner diameter of the tube is 2.0 cm. The total length of the tube is 100 cm, and each section of the tube bearing the naphthalene is 2.0 cm. Air enters the tube at a

mass flow rate of 4.5 g/min. The measured outlet mole fraction of naphthalene vapor in the exit of the tube is 0.0066, as determined by gas chromatography. The diffusion coefficient of naphthalene in air is 0:086 cm²/sat 100°C and 1.0 atm total system pressure. At this temperature and pressure, the kinematic viscosity of air is 0:25 cm²/s and the density of air is 9:5 × 10^-4 g/cm³.

a. Develop a material balance model to predict the mole fraction of naphthalene vapor exiting the tube.

b. Based on your model and the data given in the problem statement, estimate k_c.

c. Now, evaluate the mass-transfer coefficient using the appropriate established correlation and compare your results to part (b).