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. Condensation
  • B. Deaeration
  • C. Scavenging
  • D. Exhaust

Explanation: Deaeration removes air and other dissolved or entrained non-condensable gases from steam, water, or vapour systems.

Correct answer: Deaeration
  • A. Grain refining
  • B. Surface hardening
  • C. Grain coarsening
  • D. Shot peening

Explanation: Grain refinement, surface hardening, and shot peening can improve fatigue resistance by strengthening the material or introducing…

Correct answer: Grain coarsening
  • A. Injection
  • B. Calendaring
  • C. Extrusion
  • D. Blow moulding

Explanation: Blow moulding forms hollow plastic articles by inflating a heated tube or parison against the walls of a mould.

Correct answer: Blow moulding
  • A. Brasses
  • B. High carbon steels
  • C. Thermosetting polymers
  • D. Borosilicate glasses

Explanation: Season cracking is stress-corrosion cracking traditionally associated with brass, especially when residual tensile stress and ammonia or…

Correct answer: Brasses
  • A. √T
  • B. √y
  • C. 1/√P
  • D. 1/√ρ

Explanation: The sound speed is proportional to √(γP/ρ), or, for an ideal gas, to √T.

Correct answer: 1/√P
  • A. Visco-elastic
  • B. Isotropic
  • C. Elastic
  • D. Plastic

Explanation: Working above or below the recrystallisation temperature involves permanent shape change once the applied stress exceeds the yield…

Correct answer: Plastic
  • A. Fusion
  • B. Forge
  • C. Resistance
  • D. Arc

Explanation: Thermit welding uses the intense heat of an exothermic chemical reaction to melt the joint metal and filler, producing coalescence by…

Correct answer: Fusion
  • A. Silicon
  • B. Manganese
  • C. Nickel
  • D. Chromium

Explanation: The work-hardening steel used in excavator buckets and bulldozer blades is manganese steel, commonly containing iron, carbon, and a high…

Correct answer: Manganese
  • A. Polymerisation
  • B. Oxidation
  • C. Photochemical reaction
  • D. None of these

Explanation: Photosynthesis uses light energy to drive the conversion of atmospheric carbon dioxide and water into carbohydrates, so it is a…

Correct answer: Photochemical reaction
  • A. Rebound
  • B. Indentation
  • C. Dynamic
  • D. Scratch

Explanation: Mohs hardness measures scratch resistance by seeing which standard mineral can scratch another.

Correct answer: Scratch
  • A. Both B. & C.
  • B. Tin
  • C. Lead
  • D. Aluminium

Explanation: Aluminium is extracted electrolytically from alumina by the Hall-Héroult process.

Correct answer: Both B. & C.
  • A. Minor
  • B. Pitch
  • C. Major
  • D. None of these

Explanation: A screw's major diameter is the largest diameter measured over the crests of its thread and is used for its nominal specification.

Correct answer: Major
  • A. Pig
  • B. Carbon free
  • C. Wrought
  • D. Cast

Explanation: A cupola melts pig iron and scrap to produce cast iron for foundry moulds.

Correct answer: Cast
  • A. Excess of
  • B. Lack of free
  • C. Decrease in
  • D. None of these

Explanation: Heating breaks covalent bonds in the semiconductor lattice, creating additional electron-hole pairs and therefore an excess of free charge…

Correct answer: Excess of
  • A. Phosphate coating is used as an excellent base for paints & enamels
  • B. Phosphate coating is less corrosion resistant than chromate coating
  • C. The base metal to be electroplated is normally made the cathode of the electrolytic cell and
  • D. Calorising is the process of coating steel with chromium
  • E. coating metal is made the anode

Explanation: Calorising means coating steel or another metal with aluminium to improve oxidation resistance, not coating it with chromium.

Correct answer: Calorising is the process of coating steel with chromium
  • A. States that stress is inversely proportional to strain upto elastic limit
  • B. Applies beyond limit of proportionality in stress-strain curve
  • C. Applies to elastic deformation
  • D. None of these

Explanation: Hooke's law states that stress is proportional to strain within the proportional limit, which lies in the elastic region.

Correct answer: Applies to elastic deformation
  • A. Light hydrocarbon gases (e.g. butane or propane)
  • B. LPG
  • C. Petrol
  • D. None of these

Explanation: Gasohol is gasoline blended with alcohol, usually ethanol. It is therefore a petrol-alcohol fuel, not an LPG or light-gas mixture.

Correct answer: Petrol
  • A. Occurs higher in the electro-chemical series of metals
  • B. Is exemplified by magnesium plate
  • C. Is much cheaper than the cathodic base material to be guarded against corrosion
  • D. All A, B. & C.

Explanation: A sacrificial anode must be more readily oxidized than the protected pipeline, such as magnesium, and is usually inexpensive relative to…

Correct answer: All A, B. & C.
  • A. Achieve very high purity of aluminium (99.9%)
  • B. Both B. & C.
  • C. Electrolytically dissociate alumina
  • D. Keep the electrolyte in liquid condition by the generation of heat

Explanation: In the Hall-Héroult cell, electric current electrolytically decomposes dissolved alumina and the electrical resistance of the molten bath…

Correct answer: Both B. & C.
  • A. FeO
  • B. MgO
  • C. SiO2
  • D. MnO2

Explanation: Ganister is a naturally occurring siliceous refractory material, so it contains predominantly silica, SiO₂.

Correct answer: SiO2