Question

A reactor is supplied with 6 moles of N2 and 9 moles of H2, if 3 moles of NH3 is produced, how many moles of H2 are left at the end?

(a) 1.5

(b) 3

(c) 4.5

(d) 6

I have been asked this question in examination.

The query is from Species Material Balances in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering

Answer 1

The correct option is (c) 4.5

Easy explanation: The reaction is N2 + 3H2 -> 2NH3, => extent of reaction = (3 – 0)/2 = 1.5, => moles of H2 left = 9 – 1.5*3 = 4.5.