This set of Chemical Process Calculation Multiple Choice Questions & Answers (MCQs) 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)
View Answer
Explanation: 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)
View Answer
Explanation: 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
View Answer
Explanation: 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)
View Answer
Explanation: 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
View Answer
Explanation: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
View Answer
Explanation:”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. In the combustion reaction of C5H12, 9 kg of C5H12 and 172.62 kg of air are present in the feed. What is the value of the entering O2 in moles?
a) 0.25
b) 1.25
c) 2.25
d) 3.25
View Answer
Explanation: The total mass of air is given, and we need to calculate the moles of O2 in the air. The molar mass of air is approximately 28.97 g/mol, and O2 constitutes about 21% of the air. So, the moles of O2 are calculated based on this information.
8. What is the value of required O2 in moles for the combustion of C5H12, given the stoichiometric combustion reaction: C5H12 + 8O2 → 5CO2 + 6H2O?
a) 1
b) 2
c) 3
d) 4
View Answer
Explanation: The combustion of 1 mole of C5H12 requires 8 moles of O2 according to the balanced reaction. Therefore, for the stoichiometric combustion, the required O2 is directly related to the amount of C5H12 in the feed.
9. What is the percentage of excess air used in the combustion of C5H12, given that 44 kg of CO2 and 25 kg of CO are recovered in the process?
a) 25
b) 45
c) 65
d) 85
View Answer
Explanation: The excess air is calculated based on the actual amount of O2 supplied compared to the stoichiometric requirement. The percentage excess air can be found by comparing the difference between the total O2 supplied and the O2 required for complete combustion, then expressing this difference as a percentage of the required O2.
10. “Percentage excess air depends on complete combustion, not on how much material is actually burned.”
Above given statement is
a) True
b) False
c) Depends on a particular hydrocarbon
d) None of the mentioned
View Answer
Explanation: Percentage excess air depends on complete combustion, not on how much material is actually burned.
Sanfoundry Global Education & Learning Series – Chemical Process Calculation.
To practice all areas of Chemical Process Calculation, here is complete set of 1000+ Multiple Choice Questions and Answers.
