Question

Solution-1 containing 30% acetic acid and 20% nitrogen at the rate F combines with Solution-2 containing 20% acetic acid and 10% nitrogen at the rate D and Solution-3 containing 10% acetic acid and 30% nitrogen at the rate N the product formed contains 20% acetic acid at the rate P, what is the percentage of nitrogen in product?

(a) 10%

(b) 20%

(c) 30%

(d) Cannot be determined

The question was asked during an online interview.

Question is taken from Problem Solving Strategy in portion A General Strategy for Solving Material Balance Problems and Solving Material Balance Problems for Single Units of Basic Chemical Engineering

Answer 1

Correct choice is (d) Cannot be determined

The best I can explain: The equations for material balance are: 0.3F + 0.2D + 0.1N = 0.2P, F + D + N = P, and 0.2F + 0.1D + 0.3N = yP, since there are 5 variables and 3 equation, the equations cannot be solved.