An infinitely long cylinder with a diameter of 10 cm is filled with a stationary fluid. A mass input (M =0.1 g CO2) is introduced instantaneously at t = 0 at the center of the tube (x = 0). Find the time for the CO2 to reach a concentration (mass fraction) of 1 ppm at x = 50 cm for: i) Molecular diffusion in air. ii) Molecular diffusion in water. Note: (a) the densities of air and of water are 1.23 and 1000 kg/m3 respectively, (b) the diffusion coefficient of gaseous carbon dioxide is 0.14 cm2/s in air and 1.71 10-5 cm2/s in water.

Using Ficks law

DO NOT USE CHATGBT (I can tell) please just use paper and pencil.