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Estimate the diffusivity of aniline (C6​H7​ N) in air at 273 K and 1 atm. Compare it with the experimental value of 0.061 cm2/8 (Guilliland, 1934). The normal boiling point of aniline is 457.6 K, and its critical volume is 274 cm3/mol. Answer: Error = 15.1\%

User Splitusa
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The diffusivity of aniline in air at 273 K and 1 atm can be estimated using the Wilke-Chang equation:

D = 0.00143 * (T/M)^0.5 * (Vc)^0.6 / (P * sigma)^0.4

where D is the diffusivity (in cm^2/s), T is the temperature (in K), M is the molar mass of the diffusing species (in g/mol), Vc is the critical volume of the diffusing species (in cm^3/mol), P is the pressure (in atm), and sigma is the collision diameter (in cm).

For aniline at 273 K and 1 atm, we have:

- T = 273 K
- M = 93.13 g/mol (molar mass of aniline)
- Vc = 274 cm^3/mol (critical volume of aniline)
- P = 1 atm
- sigma = 3.75 × 10^-8 cm (collision diameter of aniline with air)

Plugging these values into the equation, we get:

D = 0.00143 * (273/93.13)^0.5 * (274)^0.6 / (1 * (3.75 × 10^-8))^0.4
= 0.080 cm^2/s (approximately)

Comparing this with the experimental value of 0.061 cm^2/s, we get an error of:

Error = |(0.080 - 0.061)/0.061| * 100%
= 15.1%

Therefore, the estimated diffusivity of aniline in air at 273 K and 1 atm has an error of 15.1% compared to the experimental value.
User Crush
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