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 317 of 350
- A. 1350
- B. 1715
- C. 2570
- D. 2800
Explanation: Pure silica melts at approximately 1715°C, although its crystal transformations occur at much lower temperatures.
Correct answer: 1715- A. Beryllia
- B. Alumina
- C. Thoria
- D. Zirconia
Explanation: Thoria (ThO₂) has an exceptionally high melting point of about 3300°C, higher than alumina, beryllia, and zirconia.
Correct answer: Thoria- A. Making sheaths for thermocouple
- B. Lining high temperature ceramic kilns
- C. Furnaces subjected to fluctuating temperature
- D. High frequency induction furnaces in the form of inductors
Explanation: Zirconia withstands very high temperatures and is used for thermocouple sheaths and kiln linings, but its poor thermal-shock resistance…
Correct answer: Furnaces subjected to fluctuating temperature- A. None of these
- B. Iron oxide
- C. Lime slag
- D. Molten steel
Explanation: Dolomite bricks are basic refractories containing calcium and magnesium oxides, and they resist contact with molten steel in steelmaking…
Correct answer: Molten steel- A. Low co-efficient of thermal expansion
- B. Poor thermal spalling resistance
- C. Tendency to expand unduly high during firing
- D. Very high cost
Explanation: Fireclay refractories generally have a low coefficient of thermal expansion, giving them comparatively good resistance to thermal shock.
Correct answer: Low co-efficient of thermal expansion- A. Resistance to CO attack
- B. Resistance to slag penetration
- C. RUL
- D. Permanent linear change
Explanation: The spray test evaluates how readily slag penetrates and attacks a refractory surface.
Correct answer: Resistance to slag penetration- A. 1520
- B. 1630
- C. 1670
- D. 1730
Explanation: A Seger cone above cone 33 corresponds approximately to 1730°C. PCE is a heat-resistance measurement based on the softening and bending of…
Correct answer: 1730- A. Crucibles used for melting of high purity metals
- B. Muffles for muffle furnaces
- C. Insulating bricks
- D. Segar cones
Explanation: Thoria is costly and radioactive, but its very high melting point and chemical stability allow it to be used in crucibles for melting…
Correct answer: Crucibles used for melting of high purity metals- A. 450
- B. 250
- C. 150
- D. 65
Explanation: At high temperature, fireclay brick loses much of its cold crushing strength because its structure softens and undergoes mineral…
Correct answer: 65- A. Mullite
- B. Silica
- C. High duty fireclay
- D. Carborundum
Explanation: High-duty fireclay bricks are commonly used for the walls, roofs, and combustion chambers of annealing furnaces because they tolerate high…
Correct answer: High duty fireclay6331. With increasing alumina content, the fusion point of high alumina refractories__________________?
- A. May increase or decrease; depends on its alumina content
- B. Decreases
- C. Remain constant
- D. Increases
Explanation: Increasing alumina content generally raises the refractoriness and fusion point of alumina-silica refractories.
Correct answer: Increases- A. Fusion point
- B. Spalling resistance
- C. Resistance to slag penetration
- D. Resistance to carbon monoxide attack
Explanation: PCE indicates the temperature at which a refractory cone softens and bends under its own weight, so it is used as an empirical measure of…
Correct answer: Fusion point- A. Obtaining monolithic working faces
- B. Both A. & B.
- C. Repairing construction of various furnace parts
- D. Neither A. nor B.
Explanation: Ramming masses are placed and compacted to form monolithic furnace linings or working faces, and they are also used for repairing worn…
Correct answer: Both A. & B.- A. Resistance to slag
- B. Refractoriness
- C. Crushing strength
- D. Spalling resistance
Explanation: Magnesite helps chrome-magnesite refractories withstand sudden temperature changes, so its principal benefit is improved thermal-spalling…
Correct answer: Spalling resistance- A. Fireclay bricks
- B. Tar bonded dolomite bricks
- C. Magnesite bricks
- D. Chromite bricks
Explanation: Fireclay contains a relatively high proportion of plastic clay, which loses water and contracts substantially during drying.
Correct answer: Fireclay bricks- A. Mullite
- B. Dolomite
- C. Bauxite
- D. Corundum
Explanation: Mullite, corundum, and bauxite are alumina-rich refractory materials. Dolomite is mainly calcium and magnesium carbonate, converted to…
Correct answer: Dolomite- A. Mainly contains quartz
- B. Is not stable at high temperature
- C. Transforms to other allotropic forms i.e. Tridymite and Cristobalite involving very high
- D. All A., B. and C.
- E. volume changes
Explanation: Natural silica is chiefly quartz, but quartz is not the stable high-temperature form.
Correct answer: All A., B. and C.- A. 500
- B. 1000
- C. >2000
- D. >1350
Explanation: Fireclay bricks normally retain their shape under a 2 kg/cm² load until temperatures above about 1350°C, although the exact value depends…
Correct answer: >1350- A. 200-400
- B. 100-150
- C. 50-100
- D. 500-1000
Explanation: Fireclay bricks generally have a cold crushing strength of about 200–400 kgf/cm².
Correct answer: 200-400- A. Basic Bessemer converter
- B. All A., B. and C.
- C. Electric furnaces
- D. Basic open hearth furnace
Explanation: Tar dolomite bricks resist basic slags and are used in basic Bessemer converters, basic open-hearth furnaces, and electric furnaces.
Correct answer: All A., B. and C.