All Free Chemical Engineering MCQs with Answers
Every Chemical Engineering question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
6,983 questions · page 164 of 350
- A. Left as such to protect the surface
- B. Hammered into the surface
- C. Removed with coarse emery cloth
- D. Removed by acid pickling
Explanation: Annealing can leave an oxide scale on a non-ferrous metal surface, and acid pickling dissolves this scale without mechanically damaging…
Correct answer: Removed by acid pickling- A. Copper-lead alloys
- B. Cermets
- C. Bronzes
- D. Babbitts
Explanation: Copper-lead alloys, Babbitts, and bronzes are established bearing materials because they combine load capacity with suitable friction and…
Correct answer: Cermets- A. Powder
- B. Solution
- C. Gaseous mixture
- D. Emulsion
Explanation: Shampoos are sold as powders, liquid solutions, and sometimes emulsions or creams, but a gaseous mixture cannot practically deliver the…
Correct answer: Gaseous mixture- A. None of these
- B. Smelting
- C. Roasting
- D. Classification
Explanation: Classification separates the crushed ore from unwanted particles according to size or settling behavior, so it is an ore dressing…
Correct answer: Classification- A. 150
- B. 200
- C. 300
- D. 400
Explanation: Rubber is commonly distinguished from the broader class of elastomers by an elongation exceeding about 200%, while elastomers are…
Correct answer: 2003266. Between 230 and 370°C, blue brittleness is caused in mild steel because of the_________________?
- A. Immobility of dislocation
- B. Strain-ageing
- C. Increase in Young's modulus
- D. Strain hardening
Explanation: Blue brittleness in mild steel occurs in the intermediate-temperature range because of strain ageing, in which carbon and nitrogen atoms…
Correct answer: Strain-ageing- A. Copper
- B. Nickel
- C. Aluminium
- D. Zinc
Explanation: Elinvar is a nickel-based alloy whose nearly constant elastic modulus makes it suitable for watch and instrument springs.
Correct answer: Nickel- A. He
- B. C
- C. Ar
- D. H
Explanation: The common hydrogen isotope protium has one proton and no neutron, unlike helium, carbon, and argon atoms, which contain neutrons in their…
Correct answer: H- A. Nuclear fission
- B. Nuclear fusion
- C. Both the nuclear fission & fusion
- D. Ionisation
Explanation: An atomic bomb releases energy through an uncontrolled nuclear fission chain reaction, usually involving uranium-235 or plutonium-239.
Correct answer: Nuclear fission3270. With increase in ___________________ Knocking tendency in a spark ignition petrol engine decreases?
- A. Supercharging
- B. Engine speed
- C. Compression ratio
- D. Wall temperature
Explanation: Increasing engine speed reduces the time available for the unburned end-gas to undergo auto-ignition reactions, so knocking tendency…
Correct answer: Engine speed- A. Painted steel
- B. Case hardened steel
- C. Galvanised iron
- D. Lead lined reactor
Explanation: In galvanised iron, zinc acts as a sacrificial anode and corrodes preferentially, keeping the underlying iron cathodic and protected.
Correct answer: Galvanised iron3272. Out of the following, the alloy which has equal percentage of constituents, is__________________?
- A. White metal
- B. Gun metal
- C. Duralumin
- D. Constantan
Explanation: Constantan is conventionally described in elementary alloy questions as an approximately equal-part copper-nickel alloy.
Correct answer: Constantan- A. Permeability of free space
- B. Magnetic moment
- C. Magnetic susceptibility
- D. Flux density
Explanation: Permeability has SI units N/A², equivalently T·m/A. Magnetic susceptibility is dimensionless, while flux density is measured directly in…
Correct answer: Permeability of free space- A. Phosphorous
- B. Boron
- C. Carbon
- D. Nitrogen
Explanation: Boron has three valence electrons, so replacing silicon in its crystal lattice creates holes and produces p-type conduction.
Correct answer: Boron- A. Cermets
- B. Alloy steel
- C. High speed steel
- D. Tungsten carbide
Explanation: High-speed steel retains hardness and cutting ability even when drilling generates considerable heat, while also resisting wear.
Correct answer: High speed steel- A. Season cracking of brass
- B. Caustic embrittlement of steel
- C. Neither A. nor (B)
- D. Both A. & B.
Explanation: Season cracking of brass and caustic embrittlement of steel are both forms of stress-corrosion failure, requiring a susceptible metal, a…
Correct answer: Both A. & B.- A. 3-4
- B. 12-14
- C. 0.3-0.4
- D. 20-25
Explanation: Electrical silicon steel generally contains about 3 to 4% silicon, which increases electrical resistivity and reduces eddy-current losses.
Correct answer: 3-4- A. Alumina
- B. Platinum
- C. Vanadium pentoxide
- D. Iron oxide
Explanation: Platinum is a precious-metal catalyst used in automobile catalytic converters to promote oxidation of carbon monoxide and hydrocarbons and…
Correct answer: Platinum- A. Increases the strength
- B. Decreases the free carbon
- C. Softens it to facilitate machining
- D. None of these
Explanation: Annealing cast iron reduces hardness and relieves internal stresses, making the casting softer and easier to machine.
Correct answer: Softens it to facilitate machining- A. 0.7-1.0
- B. 1.1-1.4
- C. 1.5 - 1.8
- D. 2.0 - 2.5
Explanation: Blast-furnace slag is commonly controlled with a basicity ratio near 1.1 to 1.4, based chiefly on the CaO-to-SiO2 relationship, with MgO…
Correct answer: 1.1-1.4