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 10 Kg/min, what is the percentage of nitrogen in product?

(a) 10%

(b) 20%

(c) 30%

(d) Cannot be determined

This question was posed to me by my school principal while I was bunking the class.

The doubt is from Problem Solving Strategy in section A General Strategy for Solving Material Balance Problems and Solving Material Balance Problems for Single Units of Basic Chemical Engineering

Answer 1

Correct answer is (d) Cannot be determined

Easiest explanation: The equations for material balance are: 0.3F + 0.2D + 0.1N = 0.2(10), F + D + N = 10, and 0.2F + 0.1D + 0.3N = y(10), since there are 4 variables and 3 equation, the equations cannot be solved.