Free Chemical Process Principles MCQs with Answers
2,710 Chemical Process Principles MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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- A. High amount/current of combustion air
- B. Low amount/current of combustion air
- C. Preheated secondary air
- D. Very little excess air
Explanation: A high rate or velocity of combustion air promotes rapid turbulent mixing with the gas, producing a short, intense flame.
Correct answer: High amount/current of combustion air- A. Use of thick fire bed
- B. All A., B. & C.
- C. Use of preheated primary air
- D. Low fusion point of ash (< 1100° C)
Explanation: A thick fire bed, low ash-fusion temperature and preheated primary air all raise local bed temperature or increase the amount of ash that…
Correct answer: All A., B. & C.- A. 4000
- B. 2500
- C. 6500
- D. 10000
Explanation: Gas from low-temperature coal carbonisation contains appreciable methane and other hydrocarbons, so its calorific value is higher than…
Correct answer: 6500- A. Clinkering tendency
- B. Coking tendency
- C. Caking tendency
- D. Size stability
Explanation: Ash softening temperature indicates when ash particles begin to deform and stick, which determines their tendency to form fused clinker on…
Correct answer: Clinkering tendency- A. CO2 : 6.26, CO : 1.56, O2 : 3.91, H2O :15.66, N2 : 72.60
- B. CO2 : 7.42, CO : 1.86, O2 : 4.64, N2:86.02
- C. CO2 : 6.39, CO : 1.60, O2 : 3.99, H2O:25.96, N2:72.06
- D. CO2 : 7.60, CO : 1.90, O2 : 4.75, N2 : 85.74
Explanation: For 100 mol of fuel, 64 mol CH₄ form CO₂ and 16 mol form CO; with 20% excess air, the dry products are approximately CO₂ 7.42%, CO 1.86%…
Correct answer: CO2 : 7.42, CO : 1.86, O2 : 4.64, N2:86.02- A. Preheating of fuel gases & combustion air
- B. Adopting proper fuel firing technique & fuel preparation
- C. Reducing sulphur content in the fuel
- D. Supplying correct amount of combustion air
Explanation: Sulphur reduction mainly lowers SOx emissions, corrosion, and pollution; it does not directly improve the completeness or efficiency of…
Correct answer: Reducing sulphur content in the fuel947. Tolerable concentration of toxic carbon monoxide in atmospheric air is about ______________ ppm?
- A. 50
- B. 1000
- C. 5000
- D. 10000
Explanation: About 50 ppm is the commonly quoted tolerable upper concentration for carbon monoxide in air.
Correct answer: 50- A. CH4
- B. H2
- C. CO
- D. None of these
Explanation: Blast-furnace gas contains mainly CO, nitrogen, and CO2, with some hydrogen, but methane is normally absent or negligible.
Correct answer: CH4- A. 5
- B. 15
- C. 25
- D. 50
Explanation: Coke-oven gas commonly contains roughly 20 to 30% methane, along with hydrogen, carbon monoxide, and other gases.
Correct answer: 25- A. Hydrolysis
- B. Dehydration
- C. Oxidation
- D. Fermentation
Explanation: Gobar gas forms when microorganisms anaerobically ferment or digest cow dung, producing methane-rich biogas.
Correct answer: Fermentation- A. 0.5
- B. 1.5
- C. 2.5
- D. 3.5
Explanation: Steam atomisation commonly uses approximately 0.5 kg of steam per kg of fuel oil.
Correct answer: 0.5- A. Theoretically required amount of air
- B. Theoretically required amount of oxygen
- C. Less than theoretically required amount of air
- D. More than theoretically required amount of air
Explanation: A stoichiometric quantity of pure oxygen gives the highest adiabatic flame temperature because no nitrogen is present to absorb heat and…
Correct answer: Theoretically required amount of oxygen- A. 1
- B. 7
- C. 22
- D. 46
Explanation: Coking coal generally has a volatile-matter content near 20 to 25%, making 22% a representative value.
Correct answer: 22- A. 1000
- B. 4000
- C. 8000
- D. 15000
Explanation: Dry anthracite is a high-rank coal with a calorific value commonly near 8,000 kcal/kg.
Correct answer: 8000- A. Either A. or B. without gain or loss of heat
- B. Oxygen
- C. Either A. or B.
- D. Air
Explanation: The theoretical flame temperature is the adiabatic temperature reached when fuel burns completely with the theoretical air or oxygen…
Correct answer: Either A. or B. without gain or loss of heat- A. Petrol
- B. Diesel
- C. Kerosene
- D. LPG
Explanation: Jet engines commonly use kerosene-based aviation turbine fuel because it has suitable volatility, energy content, and low-temperature…
Correct answer: Kerosene- A. Ammonia yield is more
- B. Free carbon in tar is more
- C. Aliphatic tar is produced
- D. All A., B. and C.
Explanation: Low-temperature carbonisation produces a larger quantity of tar containing more aliphatic compounds, whereas high-temperature…
Correct answer: Aliphatic tar is produced- A. Volatile matter content
- B. Ash content
- C. Moisture content
- D. CSR & CRI
Explanation: CSR measures coke strength after reaction, while CRI measures its reactivity with carbon dioxide; together they indicate whether coke can…
Correct answer: CSR & CRI- A. All A., B. and C.
- B. Lower strength
- C. Higher reactivity
- D. Lower bulk density
Explanation: Greater porosity means more void space in the coke, reducing its bulk density.
Correct answer: All A., B. and C.- A. High caking index
- B. High volatile matter content
- C. Low fusion point of ash
- D. Very low ash content (8-10%)
Explanation: Coal for producer gas should ignite readily, and higher volatile matter promotes ignition and gas formation.
Correct answer: High volatile matter content