All Free Chemical Engineering MCQs with Answers

• A. Cresylic acid
• B. Xanthaies
• C. Pine oil
• D. All A, B. & C.

Explanation: Pine oil and cresylic acid are common frothers that stabilise the froth.

• A. Better finish and surface appearance
• B. High flexibility
• C. Low impact strength
• D. High plastic deformation

Explanation: Crystalline polymers generally have greater stiffness and strength but lower flexibility and impact resistance than amorphous polymers.

• A. High % of CO in
• B. High temperature of
• C. Low temperature of
• D. High % of CO2 in

Explanation: Incomplete combustion does not oxidise all carbon to carbon dioxide, so the exhaust contains an elevated concentration of carbon monoxide.

• A. Eutectic temperature
• B. Recrystallisation temperature
• C. Lower critical temperature
• D. Upper critical temperature

Explanation: The recrystallisation temperature is the temperature at which new, strain-free grains nucleate and grow in a cold-worked metal.

• A. 25 : 1
• B. 22 : 1
• C. 14 : 1
• D. 4 : 1

Explanation: Petrol engines operate near the stoichiometric air-fuel ratio of about 14.7:1 by mass, commonly rounded to 14:1.

• A. Drain out water and sludge from the boiler during repair
• B. All A, B. & C
• C. Guard the boiler in case of abnormal rise in steam pressure
• D. Put off fire in the furnace when water level in the boiler falls to unsafe limit

Explanation: A fusible plug melts when the water level falls enough to expose it to excessive furnace heat, releasing water or steam and extinguishing…

• A. Introduces a compressive layer on the surface
• B. Enhances the yield point of the material
• C. Suppresses any stress concentration produced in the parts
• D. Produces a better surface finish

Explanation: Carburisation hardens the surface and creates a compressive residual-stress layer, which improves fatigue resistance and raises the…

• A. Authored by Kirk Othmer
• B. Edited by Kirk Othmer
• C. Edited by Perry and Chilton
• D. Authored by Perry and Chilton

Explanation: The Encyclopaedia of Chemical Technology is associated with Kirk and Othmer as editors, not as sole authors.

• A. -0.8
• B. 0.8
• C. +0.08
• D. -0.24

Explanation: For uniaxial elastic loading, lateral strain equals minus Poisson's ratio times longitudinal strain: εt = −0.3(0.8) = −0.24.

• A. Resilience
• B. Toughness
• C. Ductility
• D. Impact strength

Explanation: Resilience is the energy a material can absorb elastically and release without permanent deformation.

• A. Al2O3
• B. SiO2
• C. CaSiO2
• D. MgO

Explanation: Corundum is primarily crystalline aluminium oxide, Al2O3, commonly containing more than 95% of this compound.

• A. Copper
• B. Steel
• C. Zinc
• D. Aluminium

Explanation: The Linz-Donawitz converter is a basic oxygen furnace in which oxygen is blown through molten pig iron to reduce carbon and other…

• A. Sinter
• B. Iron ore
• C. Coke
• D. Limestone

Explanation: Coke is generally the principal sulphur-bearing material in a blast-furnace charge because it contains sulphur from the coal used in its…

• A. Zinc, copper & nickel
• B. Nickel, cobalt & vanadium
• C. Zinc, aluminium & nickel
• D. Cobalt, chromium & tungsten

Explanation: Stellite is a cobalt-base alloy whose characteristic alloying additions include chromium and tungsten, giving it high hardness, wear…

• A. Uranium - 233 : Fertile material
• B. Binding energy : Mass defect
• C. Scattering: Absorption cross-section
• D. Number of nucleons : Mass number

Explanation: Uranium-233 is a fissile material, not a fertile material; thorium-232 is the familiar fertile material that breeds uranium-233.

• A. 2
• B. 3
• C. 0.8
• D. 6

Explanation: Pig iron has a specific gravity of roughly 7, whereas blast-furnace slag is about 2.3 to 2.5.

• A. None of these
• B. H2SO3 is formed
• C. Oleum is formed
• D. Precipitation of sulphur takes place

Explanation: Sulphur dioxide and hydrogen sulphide undergo a redox reaction: 2H2S + SO2 → 3S + 2H2O.

• A. Martensitic steels are less susceptible to pitting corrosion than austenitic steels
• B. Pitting corrosion is usually very localised
• C. Hydrogen embrittlement is facilitated by tensile stress
• D. Stress corrosion cracking is facilitated by tensile stress

Explanation: Martensitic stainless steels generally have lower corrosion resistance and are more prone to pitting than austenitic stainless steels, so…

• A. Martensite forms in the heat affected zone leading to poor toughness/ductility of the weld
• B. Excessive ferrite forms in the heat affected zone leading to poor toughness of the weld
• C. Carbon and other alloying elements get oxidised from the weld pool
• D. Segregation of carbon and other element occurs in the weld pool leading to poor properties of
• E. the weld

Explanation: A high carbon equivalent increases hardenability, so rapid cooling of the heat-affected zone can produce hard, brittle martensite.

• A. Carbonate
• B. Sulphate
• C. Nitrate
• D. Chloride

Explanation: Ammonium nitrate is mixed with TNT to form amatol, a powerful explosive mixture.