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 boiling naphthenes
- B. Methane & ethane
- C. High boiling olefins
- D. Propane & butane
Explanation: Commercial LPG consists mainly of the light hydrocarbons propane and butane, supplied either separately or as a blend.
Correct answer: Propane & butane- A. Aromatics
- B. i-paraffins
- C. Naphthene
- D. Olefins
Explanation: Aromatics generally have the poorest ignition quality among the listed hydrocarbon classes and therefore the lowest cetane numbers.
Correct answer: Aromatics- A. 65
- B. 75
- C. 85
- D. 95
Explanation: Crude petroleum typically contains about 83–87% carbon by weight, with most of the remainder being hydrogen and small amounts of sulphur…
Correct answer: 85- A. Olefins
- B. Naphthenes
- C. Neither A. nor B.
- D. Both A. and B.
Explanation: The formula CₙH₂ₙ describes acyclic olefins with one double bond and monocyclic naphthenes with one ring.
Correct answer: Both A. and B.- A. Multiple proportion
- B. None of these
- C. Constant proportion
- D. Conservation of mass
Explanation: A chemical equation must conserve the number of atoms of every element on both sides.
Correct answer: Conservation of mass- A. Both B. & C.
- B. Masses
- C. Atoms
- D. Ions
Explanation: Chemical reactions rearrange atoms but do not create or destroy them, so atomic species are conserved.
Correct answer: Both B. & C.- A. Avogadro's hypothesis
- B. Conservation of mass
- C. Gaseous volumes
- D. None of these
Explanation: A balanced equation has the same number of atoms of each element on both sides, expressing conservation of mass.
Correct answer: Conservation of mass- A. Blood
- B. Intestine
- C. Saliva
- D. Gland
Explanation: Ptyalin, also called salivary amylase, begins starch digestion in the mouth and is secreted into saliva.
Correct answer: Saliva- A. Steam reforming of naphtha
- B. Gasification of carbon
- C. Thermal cracking of fuel oil
- D. Combustion of sulphur
Explanation: Combustion of sulphur releases heat, so it is exothermic rather than endothermic.
Correct answer: Combustion of sulphur- A. CO2 escapes continuously
- B. CaO is not dissociated
- C. Of high calcination temperature
- D. CaO is more stable than CaCO3
Explanation: Continuous removal of CO2 lowers its partial pressure and shifts CaCO3 decomposition toward CaO and CO2, allowing the reaction to proceed…
Correct answer: CO2 escapes continuously- A. Protons
- B. Neutrons
- C. Electrons
- D. None of these
Explanation: Chemical reactions involve rearrangement of valence electrons and changes in bonding, while protons and neutrons remain in the nuclei.
Correct answer: Electrons1732. Ore concentration by jigging is based on the difference in the ______________ of the particles?
- A. None of these
- B. Wettability
- C. Shape
- D. Specific gravities
Explanation: Jigging separates particles by their settling behaviour in a pulsating fluid, which primarily depends on differences in specific gravity.
Correct answer: Specific gravities- A. Dry grinding of large particles in un-baffed mills
- B. Wet grinding in high viscous suspension
- C. Dry grinding of large particles (upto 1.25 cms)
- D. Wet grinding in low viscous suspension
Explanation: Dry grinding of large particles in an unbaffled mill needs a higher speed so the balls are lifted sufficiently before falling and causing…
Correct answer: Dry grinding of large particles in un-baffed mills- A. Produces a coarser product
- B. Has a higher length/diameter ratio
- C. Has a higher diameter/length ratio
- D. Uses much larger balls
Explanation: A tube mill is essentially a long, narrow grinding mill, so its length-to-diameter ratio is greater than that of a ball mill.
Correct answer: Has a higher length/diameter ratio- A. Specific surface of product is more
- B. Product has lesser size uniformity
- C. Operation is economical
- D. Production rate at a given limiting size is lower
Explanation: A closed-circuit grinder sends oversize material back for further grinding and removes correctly sized product, giving better control and…
Correct answer: Operation is economical- A. None of these
- B. The size reduction ratio
- C. The change in volume due to crushing
- D. The new surface created
Explanation: Rittinger's law applies mainly to fine-size reduction, where the energy is proportional to the new surface area created.
Correct answer: The new surface created- A. Vibrating screen
- B. Trommels
- C. Shaking screen
- D. Grizzlies
Explanation: Vibrating screens have high capacity because vibration rapidly stratifies the feed and promotes repeated contact with the screening…
Correct answer: Vibrating screen- A. π = (A/D2)
- B. 2π = (2A/D2)
- C. π/6 = (V/D3)
- D. AD/V
Explanation: For a sphere, the volume is V = πD³/6, so dividing by D³ gives V/D³ = π/6. This is the volume shape factor for spherical particles.
Correct answer: π/6 = (V/D3)- A. Tube mills
- B. Ball mills
- C. Compartment mills
- D. Jaw crushers
Explanation: Jaw crushers perform coarse size reduction rather than fine grinding. Basic slag is ground in mills such as ball, compartment, or tube…
Correct answer: Jaw crushers- A. Jigging & tabling
- B. Froth floatation
- C. Flocculation
- D. None of these
Explanation: Jigging and tabling use gravity differences to concentrate the comparatively dense iron-bearing particles from gangue.
Correct answer: Jigging & tabling