Question

100 Kg of a gas mixture of 40% He and 60% Ne is passed through a diffusion tube and the product has 20% He and 80% Ne, what is the amount of He recovered?

(a) 25 Kg

(b) 45 Kg

(c) 50 Kg

(d) 75 Kg

The question was posed to me in class test.

This is a very interesting question from Solving Material Balance Problems for Single Units topic in chapter A General Strategy for Solving Material Balance Problems and Solving Material Balance Problems for Single Units of Basic Chemical Engineering

Answer 1

The correct choice is (a) 25 Kg

The explanation is: Let the amount of He recovered be D, He Balance: 0.4(100) = 1(D) + 0.2(100 – D), => D = 25 Kg.