Free Plant Design and Economics MCQs with Answers

• A. Annealing
• B. Tempering
• C. Normalising
• D. Spheroidising

Explanation: Spheroidising changes lamellar cementite into rounded particles, reducing resistance to cutting and improving machinability, particularly…

• A. Lead
• B. Mild steel
• C. Copper
• D. Special alloys

Explanation: Lead resists attack by dilute sulphuric acid because it develops a protective insoluble sulphate layer.

• A. Die
• B. True centrifugal
• C. Slush
• D. Investment

Explanation: Pipes are commonly made by true centrifugal casting, in which molten metal is forced against a rotating mould wall to produce a dense…

• A. Cast iron
• B. Refractory blocks
• C. Stainless steel
• D. Lead lined steel

Explanation: Urea autoclaves handle hot, concentrated urea solutions that are highly corrosive, so stainless steel is selected for its corrosion…

• A. Steel drum
• B. Cast iron vessel
• C. Cast iron vessel lined with acid-proof masonry brick
• D. Stainless steel vessel

Explanation: Stainless steel is passivated by nitric acid and therefore resists corrosion during storage.

• A. Iron
• B. Vanadium
• C. Tungsten
• D. Cobalt

Explanation: Invar is mainly an iron-nickel alloy containing roughly 64% iron and 36% nickel.

• A. 5
• B. 10
• C. 20
• D. 0

Explanation: German silver is a copper-nickel-zinc alloy and contains no silver despite its name.

• A. None of these
• B. Karbate
• C. Cast iron
• D. Monel

Explanation: Monel has excellent resistance to chloride-containing solutions, including concentrated brine, because of its nickel-copper composition.

• A. Magnetic properties
• B. Ductility
• C. Corrosion resistance
• D. Cutting hardness

Explanation: Tungsten forms hard alloy carbides and raises the hot hardness and wear resistance of steel, which is essential for cutting tools.

• A. Cast iron containers
• B. Galvanised or tin lined drums
• C. Boxed glass carboys
• D. Nickel lined steel tank cars

Explanation: Phenol is commonly shipped in nickel-lined steel tank cars, lined drums, or glass carboys, but cast iron is unsuitable because phenol can…

• A. 4
• B. 8
• C. 14
• D. 20

Explanation: Acid-resistant cast iron is made by adding a high silicon content, typically about 14 to 16%, which promotes formation of a protective…

• A. Yield point
• B. Ultimate tensile strength (UTS)
• C. Ductility
• D. None of these

Explanation: Normalising refines the grain structure and generally raises strength and hardness compared with the soft annealed condition, but it…

• A. None of these
• B. Cast iron and aluminium
• C. Stainless steel and high silicon cast iron
• D. PTFE and porcelain

Explanation: Concentrated hydrochloric acid is highly corrosive to ordinary metals, especially aluminium and many steels.

• A. Copper, aluminium and silver
• B. Copper, nickel and zinc
• C. Silver, zinc and aluminium
• D. Silver, nickel and zinc

Explanation: German silver contains copper, nickel and zinc, despite its name and silvery appearance.

• A. Decreases its tensile strength
• B. Increases its ductility
• C. Decreases its ductility
• D. Does not affect its ductility

Explanation: Plastic deformation during work hardening increases dislocation density, making further deformation more difficult and raising tensile…

• A. Cobalt
• B. None of these
• C. Nickel
• D. Zinc

Explanation: Zinc is a non-ferromagnetic metal, whereas cobalt and nickel are ferromagnetic. Therefore zinc is the non-magnetic choice.

• A. Austenitic
• B. Ferritic
• C. Martensitic
• D. None of these

Explanation: 18/8 stainless steel contains approximately 18% chromium and 8% nickel.

• A. Brittleness
• B. Ductility
• C. Toughness
• D. Malleability

Explanation: Percentage elongation measures how much a specimen stretches plastically before fracture, so it is a standard measure of ductility.

• A. Dilute HCI
• B. Concentrated H2SO4
• C. Acetic acid
• D. None of these

Explanation: Acetic acid attacks lead and can form soluble or weakly protective lead compounds, allowing corrosion to continue.

• A. Suppresses the decomposition of Fe3C
• B. Reduces its fluidity
• C. Increases the contraction of the metal
• D. Increases the formation of graphite

Explanation: Silicon promotes graphitisation in cast iron by encouraging decomposition of cementite, Fe₃C, into iron and graphite.