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. Copper
- B. Tin
- C. Zinc
- D. Aluminium
Explanation: Fire refining is commonly used for blister copper, where oxidation removes impurities and subsequent reduction lowers the dissolved…
Correct answer: Copper2522. The two elements required to form substitutional solid solution should not have___________________?
- A. Same crystalline structure
- B. Widely differing electronegativity
- C. Same valency
- D. Same atomic sizes
Explanation: Substitutional solid solubility is favoured by similar atomic sizes, crystal structures, valencies and electronegativities.
Correct answer: Widely differing electronegativity- A. Critical point
- B. Inversion temperature
- C. Curie temperature
- D. Eutectic temperature
Explanation: Curie temperature is the critical temperature above which a ferromagnetic material loses its spontaneous magnetism and becomes…
Correct answer: Curie temperature- A. Hardness & tensile strength
- B. Carbon content
- C. Iron content
- D. Alloying elements content
Explanation: The primary designation of steel is based on its chemical composition, especially the alloying elements present.
Correct answer: Alloying elements content- A. Intensifies deterioration
- B. Changes the composition of the metal
- C. None of these
- D. Inhibits further deterioration
Explanation: Passivation forms a protective surface film, often an adherent oxide, that sharply reduces the rate of further corrosion.
Correct answer: Inhibits further deterioration- A. Toughness
- B. Machinability
- C. Internal stress level
- D. Softness
Explanation: Tempering relieves internal stresses, reduces hardness and improves toughness, while machinability is chiefly improved by processes such…
Correct answer: Machinability- A. A high temperature neutral gas
- B. A source of steady and highest controllable pressure
- C. Nothing but ionised gas
- D. Formed at very low temperature
Explanation: Plasma is a high-temperature state of matter containing freely moving ions and electrons, so it is commonly described as ionised gas.
Correct answer: Nothing but ionised gas- A. Conductor
- B. Insulator
- C. None of these
- D. Semi-conductor
Explanation: Semiconductors occupy the intermediate resistivity range between conductors and insulators; a resistivity of about 1 to 100 ohm·cm falls…
Correct answer: Semi-conductor2529. The most important requirement for aluminium industry is the availability of cheap _______________?
- A. Electrical power
- B. Ore
- C. Labour
- D. Abundant water
Explanation: Aluminium is produced electrolytically from alumina by the Hall-Héroult process, which consumes a very large amount of electricity.
Correct answer: Electrical power- A. Are magnetised by eddy currents only
- B. Are magnetised in direction opposite to the magnetic field
- C. Are non-magnetic and cannot be magnetised
- D. Can be magnetised in one direction only
Explanation: Diamagnetic substances develop an induced magnetic moment opposite to the applied magnetic field, producing weak repulsion.
Correct answer: Are magnetised in direction opposite to the magnetic field- A. Decrease in dislocation density
- B. Increase in solutionising temperature
- C. Increase in strength
- D. Decrease in grain size
Explanation: Fine-grained steel has more grain boundaries, which hinder the growth of martensite during quenching and reduce hardenability.
Correct answer: Decrease in grain size2532. Brittleness induced due to the presence of sulphur in steel can be reduced by adding______________?
- A. Copper
- B. Magnesium
- C. Vanadium
- D. Manganese
Explanation: Manganese combines preferentially with sulphur to form manganese sulphide (MnS), preventing iron sulphide from producing hot shortness or…
Correct answer: Manganese- A. Simple cubic
- B. Face centred
- C. Body centred
- D. None of these
Explanation: Face-centred cubic crystals have the greatest packing efficiency, about 74%, compared with about 68% for body-centred cubic and 52% for…
Correct answer: Face centred- A. H2SO4
- B. NH3
- C. NaOH
- D. HCl
Explanation: In the Bayer process, bauxite is digested under pressure with concentrated sodium hydroxide, which dissolves alumina as soluble sodium…
Correct answer: NaOH- A. Tempering
- B. Toughening
- C. Work hardening
- D. Annealing
Explanation: Annealing the welded portion relieves residual stresses and reduces the brittleness caused by the welding thermal cycle.
Correct answer: Annealing- A. Length
- B. Shank diameter
- C. Head diameter
- D. None of these
Explanation: For a bolt under a given load, elastic strain energy varies directly with its length, so increasing length increases resilience.
Correct answer: Length- A. Magnesite
- B. Silica
- C. Chrome
- D. Fireclay
Explanation: Silica refractories resist thermal shock at high temperature but undergo a volume change during the quartz-to-cristobalite transformation…
Correct answer: Silica- A. Amorphous
- B. Homogeneous
- C. Cellular
- D. Granular
Explanation: Wood is cellular because it consists of a network of cells and pores formed by its biological growth.
Correct answer: Cellular- A. Cold heading
- B. Casting
- C. Sintering
- D. Spinning
Explanation: Small steel balls are commonly produced by cold heading, in which wire segments are forced into spherical dies, followed by flashing…
Correct answer: Cold heading- A. Highly stressed parts
- B. Gauges or precision parts
- C. Cold rolled sheets
- D. Non machinable materials
Explanation: Sub-zero treatment is commonly applied to gauges and precision components to improve dimensional stability after hardening.
Correct answer: Gauges or precision parts