Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) on “Multiple Component Systems”.
1. Feed of a reactor has 0.25 mass fraction of H2O and 0.75 mass fraction of CO2 with rate 4 g/hr, if the product rate is 20 g/hr what is the mass of CO2 in the product side?
a) 3 grams
b) 9 grams
c) 15 grams
d) 21 grams
Answer: c
Clarification: Mass fraction of CO2 will be same on both sides, => mass of CO2 in the product side = 20*0.75 = 15 grams.
2. A reactor has feed of two streams, stream 1 has CO2 and H2O with mass fraction of 0.4 and 0.6 and rate 10 kg/hr, and stream 2 has CO2 and H2O with mass fraction 0.1 and 0.9 and rate 40 Kg/hr, what the mass fraction of CO2 in the product stream?
a) 0.08
b) 0.16
c) 0.24
d) 0.32
Answer: b
Clarification: Mass fraction of CO2 in product stream = (0.4*10 + 0.1*40)/(10 + 40) = 0.16.
3. A reactor has feed from 2 streams, one with rate 10 Kg/hr and other with 30 Kg/hr, and product side also has 2 streams one of which is at the rate of 15 Kg/hr, what is the rate of other product stream?
a) 5 Kg/hr
b) 15 Kg/hr
c) 25 Kg/hr
d) 35 Kg/hr
Answer: c
Clarification: Total feed rate = Total product rate, => 10 + 30 = 15 + x, => x = 25 Kg/hr.
4. Feed of a reactor has 0.75 mass fraction of O2 and some SO2, if the product rate is 1000 Kg/hr then what is the rate of SO2 in the feed?
a) 100 Kg/hr
b) 250 Kg/hr
c) 750 Kg/hr
d) 1000 Kg/hr
Answer: b
Clarification: Feed rate = Product rate = 1000 Kg/hr, => Rate of SO2 = (1 – 0.75)*1000 = 250 Kg/hr.
5. A reactor has two feed streams with the ratio of their rate as 1:9 and has O2 and O3 with the mass fraction of 0.6 and 0.4 in stream 1 and 0.2 and 0.8 in stream 2, what is the mass fraction of O2 in the product side?
a) 0.24
b) 0.48
c) 0.72
d) 0.96
Answer: a
Clarification: Let the stream rates be 1 Kg/hr and 9 Kg/hr, => mass fraction of O¬2 in product side = (1*0.6 + 9*0.2)/(1 + 9) = 0.24.
6. A reactor with efficiency 50%, has the feed CO2 and SO2 with mass fraction 0.4 and 0.6 with the rate 10 Kg/hr, what is the rate of CO2 in product side?
a) 0.5 Kg/hr
b) 1 Kg/hr
c) 1.5 Kg/hr
d) 2 Kg/hr
Answer: d
Clarification: Rate at product side = 10*50/100 = 5 Kg/hr, => rate of CO2 = 5*0.4 = 2 Kg/hr.
7. A reactor has feed rate of 10 Kg/ hr and 5 Kg/hr and product rate of 9 Kg/hr, what is the efficiency of the reactor?
a) 10%
b) 30%
c) 60%
d) 100%
Answer: c
Clarification: Efficiency = 9/(10 + 5)*100 = 60%.
8. Waste water flowing with TSS concentration 40 mg/L at the rate of 10 Liter/min is discharged into the river if the river is flowing at the rate of 15 Liter/min, what is the concentration of TSS in the river?
a) 10 mg/L
b) 30 mg/L
c) 45 mg/L
d) 60 mg/L
Answer: d
Clarification: Concentration of TSS in river = 40*15/10 = 60 mg/L.
9. Water flowing with chlorine concentration 10 mg/L at the rate of 20 Liter/min, is discharged into a river if the concentration of chlorine in a river is 5 mg/L what is the flow rate of river?
a) 10 Liter/min
b) 20 Liter/min
c) 30 Liter/min
d) 40 Liter/min