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. Ammonium carbamate
- B. Biuret
- C. Ammonium carbonate
- D. None of these
Explanation: Urea manufacture first forms ammonium carbamate from ammonia and carbon dioxide, which then dehydrates to urea and water.
Correct answer: Ammonium carbamate- A. Nickel
- B. Reduced iron oxide
- C. Vanadium pentoxide
- D. Silica gel
Explanation: The Haber process uses an iron catalyst, generally prepared by reducing promoted magnetite or iron oxide to active iron.
Correct answer: Reduced iron oxide- A. 10
- B. 30
- C. 50
- D. 70
Explanation: Wet-process phosphoric acid commonly contains about 28 to 32% P2O5, so 30% is the suitable approximate value.
Correct answer: 30- A. Mono-ethanolamine (MEA)
- B. Slaked lime
- C. Ammoniacal liquor
- D. Methyl-Ethyl Ketone (MEK)
Explanation: MEA chemically absorbs acidic CO2 from reformed gas and can later be regenerated, making it suitable for continuous gas purification.
Correct answer: Mono-ethanolamine (MEA)- A. O2
- B. H2
- C. CO2
- D. N2
Explanation: Synthesis gas is mainly a mixture of hydrogen and carbon monoxide, and hydrogen is the listed essential component.
Correct answer: H2- A. Osmotic pressure of the soil water becomes less than that of the plant sap
- B. Soil becomes too alkaline
- C. Osmotic pressure of the soil water becomes higher than that of the plant sap
- D. Soil becomes too acidic
Explanation: Fertiliser salts raise the soil-solution concentration, so its osmotic pressure becomes higher than that of the plant sap.
Correct answer: Osmotic pressure of the soil water becomes higher than that of the plant sap327. During conversion of ammonium carbamate into urea, presence of large excess of water______________?
- A. Increases the yield of urea
- B. Does not affect the yield of urea
- C. Reduces the evaporator load by diluting the urea solution
- D. Adversely affects the yield of urea
Explanation: Urea formation from ammonium carbamate is an equilibrium reaction that produces water, so excess water shifts the equilibrium backward and…
Correct answer: Adversely affects the yield of urea- A. Gasify coal to get hydrogen from coal gas
- B. Use coal for heating purpose
- C. Use coal as filler in fertiliser
- D. Use coal as conditioner in fertiliser
Explanation: These coal-based fertiliser plants gasify coal to produce synthesis gas, from which hydrogen is obtained for ammonia manufacture.
Correct answer: Gasify coal to get hydrogen from coal gas- A. 120°C and 300 atm
- B. 190°C and 200 atm
- C. 400°C and 550 atm
- D. 200°C and 10 atm
Explanation: Industrial urea synthesis is carried out near 190°C and about 200 atm so that ammonia and carbon dioxide remain reactive and the…
Correct answer: 190°C and 200 atm- A. Ammonium carbonate
- B. Ammonium carbamate
- C. Carbon dioxide
- D. Biuret
Explanation: Biuret forms when urea condenses at elevated temperature, especially during concentration or prolonged heating, and it can injure plants…
Correct answer: Biuret- A. Potassium sulphate
- B. Potassium chloride
- C. A mixture of NaCl + KCl
- D. None of these
Explanation: Commercial potassium sulphate is commonly graded at about 50% K2O equivalent, whereas potassium chloride is normally about 60% K2O…
Correct answer: Potassium sulphate- A. Low bulk density product
- B. Biuret formation
- C. Non-spherical prills
- D. Substantially wet non-flowing and sticky product
Explanation: Excess residence time just above the melting point promotes condensation of urea to biuret.
Correct answer: Biuret formation- A. Presence of an inert atmosphere
- B. Absence of air
- C. Presence of a reducing atmosphere
- D. Presence of an oxidising atmosphere
Explanation: Yellow phosphorus is heated at about 250–450°C without air to prevent oxidation while its molecular structure changes to the red form.
Correct answer: Absence of air- A. 15-17
- B. 8-10
- C. 3-4
- D. 20-25
Explanation: Natural gas consists mainly of methane, with smaller amounts of ethane and other hydrocarbons.
Correct answer: 3-4335. C/H ratio (by weight) of naphtha used in nitrogenous fertiliser making is about_________________?
- A. 2
- B. 6
- C. 13
- D. 20
Explanation: Naphtha contains hydrocarbons with a typical carbon-to-hydrogen mass ratio near 6.
Correct answer: 6- A. 200 atm, 1000°C
- B. 450 atm, 550°C
- C. 450 atm, 200°C
- D. 450 atm, 1000°C
Explanation: Ammonia synthesis uses high pressure and a moderately high temperature, commonly around 400–550°C.
Correct answer: 450 atm, 550°C- A. 250-300
- B. 500-750
- C. 950-1050
- D. 1400-1450
Explanation: Phosphate rock is reduced with silica and carbon in an electric furnace, where the fusion zone must be maintained near 1400–1450°C.
Correct answer: 1400-1450- A. Superphosphate
- B. Dicalcium phosphate
- C. Triple superphosphate
- D. None of these
Explanation: Ordinary superphosphate commonly contains about 16–20% available P2O5, whereas dicalcium phosphate and triple superphosphate have…
Correct answer: Superphosphate- A. Superphosphate
- B. Triple superphosphate
- C. Meta-phosphoric acid
- D. Monoammonium phosphate
Explanation: Phosphate rock reacts with phosphoric acid to produce triple superphosphate, which is mainly monocalcium phosphate.
Correct answer: Triple superphosphate- A. Corrosive in nature
- B. Helpful in decomposition of urea
- C. Toxic and harmful to some crops
- D. Explosive in nature
Explanation: Biuret can inhibit seed germination and damage or become toxic to sensitive crops, so its concentration in urea is controlled below about…
Correct answer: Toxic and harmful to some crops