A stream of air at 100 kPa pressure and 300 K is flowing on the top surface of a thin flat sheet of solid naphthalene of length 0.2 m with a velocity of 20 m/sec. The other data are:Mass diffusivity of naphthalene vapor in air = 6 * 10 –6 m2/secKinematic viscosity of air = 1.5 * 10 –5 m2.scConcentration of naphthalene at the air-solid naphthalene interface = 1 * 10 – 5 kmol/m3Calculate the overage mass transfer coefficient over the flat plate.Note: For heat transfer over a flat plate, convective heat transfer coefficient for laminar flow can be calculated by the equation.Nu = 0.664 ReL1/2 Pr1/3you may use analogy between mass and heat transfer.

• A. 0.014 m/sec
• B. 0.015 m/sec
• C. 0.016 m/sec
• D. 0.013 m/sec