Question

A reactor is supplied with 25 moles of C, and it undergoes following reactions C + 0.5O2 -> CO and C + O2 -> CO2, if 13 moles of CO2 was produced and 5 moles of C remains unreacted, what are the number of moles of CO produced?

(a) 1

(b) 3

(c) 5

(d) 7

This question was addressed to me in unit test.

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

Answer 1

Right choice is (d) 7

For explanation: Extent of second reaction = (13 – 0)/1 = 13, => moles of C reacted in second reaction = 13*1 = 13, => moles of C reacted in first reaction = 25 – 13 – 5 = 7, => extent of first reaction = (0 – 7)/(-1) = 7, => moles of CO produced = 7*1 = 7.