Question

What is the fraction of a gas in a system at partial pressure 2 mm Hg, if the 0.2 fraction of the same gas is at partial pressure 8 mm Hg and 0.3 fraction at partial pressure 18 mm Hg (Use Freundlich Isotherm)?

(a) 0.0125

(b) 0.0250

(c) 0.0375

(d) 0.0450

This question was posed to me in an interview for job.

This is a very interesting question from Liquids and Gases in Equilibrium with Solids topic in chapter Liquids and Gases in Equilibrium with Solids and Energy: Terminology, Concepts, and Units of Basic Chemical Engineering

Answer 1

The correct answer is (a) 0.0125

For explanation: y1/y2 = (p1/p2)^n, => 0.2/0.3 = (8/18)^n => n = 2, => 0.2 = k*8^2 = k = 0.2/64, => y = 0.2/64*2^2 = 0.0125.