All Free Chemical Engineering MCQs with Answers

• A. Malleable
• B. Ductile
• C. Tough
• D. Brittle

Explanation: Phosphorus makes steel brittle by promoting brittleness, especially at lower temperatures, so phosphatic iron produces brittle steel.

• A. Resistance to vegetable acids as the tin plate are commercially used in 'canning' industry
• B. Abundant availability
• C. Lower cost
• D. None of these

Explanation: Tin is used on steel cans because it resists attack by vegetable acids and food materials, making it suitable for the canning industry.

• A. Nitrous oxide
• B. Nitric oxide
• C. Nitrogen trioxide
• D. Nitrogen pentoxide

Explanation: Nitrous oxide, N₂O, is called laughing gas because inhalation can produce euphoria and laughter.

• A. 75-100
• B. 200-300
• C. 350-450
• D. 500-600

Explanation: Tempering is commonly carried out in the moderate range of about 200–300°C to reduce brittleness while retaining useful hardness.

• A. Is due to intermolecular forces of cohesion
• B. Decreases with rise in temperature
• C. All A, B. & C
• D. Is responsible for the spherical shape of an isolated liquid drop

Explanation: All three statements describe surface tension: cohesive molecular forces produce it, increasing temperature reduces it, and minimising…

• A. Tension
• B. Vibration
• C. Fatigue
• D. Shock loading

Explanation: Resilience is the ability to absorb energy elastically and release it without permanent deformation.

• A. Machinability
• B. Corrosion resistance
• C. Fluidity
• D. Strength

Explanation: Lead forms a soft, discontinuous phase in brass that breaks chips and provides lubrication at the cutting tool.

• A. H2SO3
• B. HF
• C. HNO3
• D. K2Cr2O7

Explanation: Hydrofluoric acid attacks silica, the principal constituent of ordinary glass, forming volatile or soluble silicon fluoride products.

• A. Extrusion
• B. Bending
• C. Forging
• D. Rolling

Explanation: Cold heading or upsetting compresses a portion of a metal blank to increase its cross-sectional area, commonly forming bolt heads.

• A. Iron
• B. Copper
• C. Titanium
• D. Aluminium

Explanation: Aluminium is the most abundant metal in the Earth’s crust, although oxygen and silicon are more abundant elements overall.

• A. Impact
• B. Completely reversed
• C. Dynamic
• D. Static & dynamic

Explanation: Endurance strength is determined from fatigue testing, commonly using a cyclic stress that alternates between equal tensile and…

• A. Machinability
• B. Endurance limit
• C. Impact strength
• D. Corrosion resistance

Explanation: A notched bar concentrates stress at the notch, and the impact test measures the energy absorbed during sudden fracture.

• A. lbm/lbf. ft/sec2
• B. lbf/lbm. ft/sec2
• C. ft/sec2
• D. lbm/lbf. sec2/ft

Explanation: In the British engineering system, gc converts between lbm, lbf, feet and seconds, with units lbm·ft/(lbf·s²).

• A. Petrol & diesel
• B. Lignite & coal gas
• C. Lignite & anthracite coal
• D. Coal gas & natural gas

Explanation: Petrol and diesel are both hydrocarbon fuels with very similar mass-based calorific values, generally around 44 to 46 MJ/kg.

• A. Approximately 80% of the aluminium deposited on the cathode comes from cryolite
• B. The electrolyte consists of molten Na3AlF6 with approximately 1 to 8% Al2O3
• C. Sodium is deposited along with aluminium, but is immediately vaporised
• D. Anode effect sets in when the cryolite concentration goes below 40%.

Explanation: In the Hall-Héroult process, alumina is dissolved in molten cryolite, typically at about 1 to 8% concentration.

• A. Iron ore & coke
• B. Iron ore, coke & air
• C. Limestone, coke & iron ore
• D. Limestone, sand & iron ore

Explanation: The solid charge normally consists of iron ore, coke and limestone. Air is blown into the furnace as the blast, so it is not usually…

• A. 0.2 to 0.4
• B. 0.01 to 0.10
• C. 0.5 to 0.7
• D. 0.8 to 1.0

Explanation: Martensite hardness rises most sharply as carbon increases through approximately the 0.2 to 0.4% range, because carbon strongly…

• A. Stainless steel
• B. High speed steel
• C. Mild steel
• D. High carbon steel

Explanation: High-speed steel retains hardness at the elevated temperatures produced during drilling, while ordinary mild and carbon steels soften more…

• 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.

• 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…