3. An Arnold cell is used to measure the diffusivity of chloroform in air at 25C and 1 atm (1.013x105 N/m) pressure. The liquid density of chloroform at 25C is 1485 kg/m, and its vapour pressure is 0.263 atm. At the beginning of the test the liquid chloroform surface was 72 mm from the top of the tube and after 10 hours it had dropped a further 4.4 mm. If pure air flows across the top of the tube, what is the gas diffusion coefficient of chloroform in air? Given: R=8.314 Nm/mol K