250+ TOP MCQs on Material balances for a Combustion System-II and Answers

Chemical Process Calculation Aptitude Test focuses on “Material balances for a Combustion System-II”.

1. The quantity of oxygen required to completely oxidize all the organic and inorganic compounds present in a sample is called
a) Total Oxygen Demand (TOD)
b) Chemical Oxygen Demand (COD)
c) Biochemical Oxygen Demand (BOD)
d) Theoretical Oxygen Demand (TOD)
Answer: a
Clarification: The quantity of oxygen required to completely oxidize all the organic and inorganic compounds present in a sample is called Total Oxygen Demand.

2. The quantity of oxygen required to completely oxidize all the organic compounds present in a sample is called
a) Total Oxygen Demand (TOD)
b) Chemical Oxygen Demand (COD)
c) Biochemical Oxygen Demand (BOD)
d) Theoretical Oxygen Demand (TOD)
Answer: b
Clarification: The quantity of oxygen required to completely oxidize all the organic compounds present in a sample is called Chemical Oxygen Demand.

3. The COD value is ________than the BOD value.
a) Lower
b) Higher
c) Depends on a particular sample
d) None of the mentioned
Answer: b
Clarification: COD includes slowly biodegradable and recalcitrant organic compounds not degraded by microorganisams as in BOD test.

4. The quantity of oxygen required by microorganisms to oxidize the organic compounds in a sample as deter present in a sample is called
a) Total Oxygen Demand (TOD)
b) Chemical Oxygen Demand (COD)
c) Biochemical Oxygen Demand (BOD)
d) Theoretical Oxygen Demand (TOD)
Answer. c
Clarification: The quantity of oxygen required by microorganisms to oxidize the organic compounds in a sample as deter present in a sample is called Biochemical Oxygen Demand.

5. For BOD test, incorrect statement is
a) The test is carried out for number of days at 20 degree celsius
b) Five days is the most common duration
c) both a and b
d) None of the mentioned
Answer: d
Clarification:The test is carried out for number of days at 20 degree celsius for five days.

6. “In BOD test, the quantity of O₂ used is determined by the difference in the dissolved O₂ in the water in the beginning of the test and at the end of five days”
above given statement is
a) True
b) False
c) Not sufficient data
d) None of the mentioned
Answer: a
Clarification:”In BOD test, the quantity of O₂ used is determined by the difference in the dissolved O₂ in the water in the beginning of the test and at the end of five days.

7-9. For the combustion reaction of C₅H₁₂, 9 kgs of C₅H₁₂ and 172.62 kgs of air is there in the feed. 44 kgs of CO₂ and 25 kgs of CO is recovered in the process.
C₅H₁₂ + 8o₂ → 5CO₂ + 6H₂O

7. What is value of entering O₂ in moles?
a) 0.25
b) 1.25
c) 2.25
d) 3.25
Answer: b
Clarification: Entering O₂ means the O₂ available in the feed.

8. What is the value of required O₂ in moles?
a) 1
b) 2
c) 3
d) 4
Answer: a
Clarification: Oxygen required by the substrate is required O₂.

9. What is the percent excess air?
a) 25
b) 45
c) 65
d) 85