Hydrogen gas at 1 std atm. and 25 C flows through a pipe made of unvulcanized Neoprene rubber with ID and OD of 25 and 50 mm respectively. If the concentration of Hydrogen at the inner surface of the pipe is 2.37 x 10 kmole Hydrogen/'m and the diffusivity of Hydrogen gas through the rubber is 1.8 x 10-6 cm /s, estimate the rate of loss of Hydrogen by diffusion through a pipe of 2 m length. The outside air may be assumed to be free from Hydrogen. (8-12) (May/June '06) (April/May '08)