250+ TOP MCQs on Metal as Packaging Material and Answers

Food Packaging Technology Multiple Choice Questions & Answers on “Metal as Packaging Material”.

1. Which of the following metal is not used in food packaging?
a) Aluminum
b) Iron
c) Tin
d) Chromium
Answer: b
Clarification: Iron is not used in food packaging. Iron has greater chances of rusting. For food packaging, four types of metal are commonly used: steel, aluminum, tin, and chromium.

2. Steel and aluminum are primary materials for metal packaging.
a) True
b) False
Answer: a
Clarification: The given statement is true. Steel and aluminum are commonly used in production of food cans, and are the primary materials for metal packaging.

3. Beverage cans are usually produced from steel.
a) True
b) False
Answer: b
Clarification: The given statement is false. Food cans are most often made of steel, and beverage cans are usually produced from aluminum.

4. ________ is used as protective layer for steel.
a) Chromium
b) Aluminum
c) Boron
d) Iron
Answer: a
Clarification: Steel tends to oxidize when it is exposed to moisture and oxygen, producing rust. Therefore, chromium is used as protective layers for steel. If chromium is used to provide corrosion protection, the resulting material is called electrolytic chromium- coated steel (ECCS) or tin-free steel (TFS). ECCS has better heat resistance than tinplate and is less expensive.

5. Tin is used as a protective layer in steel.
a) True
b) False
Answer: a
Clarification: The given statement is true. Tin is used as protective layers for steel. Tinplate is a composite of tin and steel made by electrolytic coating of bare steel with a thin layer of tin to minimize corrosion. Tinplate is more resistant to corrosion than electrolytic chromium- coated steel (ECCS).

6. A metal can is a ________ package.
a) primary
b) secondary
c) tertiary
d) quaternary
Answer: a
Clarification: A metal can is a primary package. The package which is in direct contact with the contained product, providing initial and most crucial protective barrier is known as a primary package. Its main function is containment.

7. __________ is added to aluminum to improve strength of the alloy.
a) Titanium
b) Chromium
c) Magnesium
d) Tin
Answer: c
Clarification: Magnesium is added to aluminum to improve strength. It also increases its strain hardening ability. These alloys are the highest strength non heat-treatable aluminum alloys and hence are used widely for structural applications.

8. The aluminum-copper alloys typically contain between ______% copper.
a) 15-30
b) 15-20
c) 10-20
d) 2-10
Answer: d
Clarification: The aluminum-copper alloy contains between 2-10 % copper. Copper helps in the strength and stability of the alloy.

9. Copper increases the hardness of alloys.
a) True
b) False
Answer: a
Clarification: Copper increases tensile strength, fatigue strength and hardness of the alloys due to the effect of solid solution hardening. It helps to strengthen the alloys by precipitation hardening heat treatment. It decreases the ductility and corrosion resistance of the alloys.

10. _______ increases susceptibility of the alloys to Stress corrosion cracking.
a) Silicon
b) Lead
c) Iron
d) Zinc
Answer: d
Clarification: Zinc increases susceptibility of the alloys to Stress corrosion cracking. But addition of zinc to aluminum has some benefits. Zinc, in aluminum alloy increases strength and allows precipitation hardening. Zinc and aluminum alloy is heat-treatable and has a very high strength.

11. Chromium is added to aluminum alloy to __________
a) prevent recrystallisation
b) increase impact strength
c) increase abrasion resistance
d) prevent cracking
Answer: a
Clarification: Chromium is added to aluminum to prevent recrystallization in aluminum alloys during heat treatment by controlling grain structure, to prevent grain growth in aluminum alloys. Chromium also reduces stress corrosion susceptibility and improves toughness.

12. ______ is added to aluminum alloys to reduce the coefficient of expansion.
a) Zinc
b) Chromium
c) Nickel
d) Manganese
Answer: c
Clarification: Nickel is added to aluminum alloys to reduce the coefficient of expansion. It also improves hardness and strength at elevated temperatures. Nickel is also added to aluminum-copper and aluminum-silicon alloys for the same.

13. ________ is added to aluminum alloys to increase Young’s modulus.
a) Chromium
b) Magnesium
c) Boron
d) Lithium
Answer: d
Clarification: Lithium is added to aluminum alloys to increase Young’s modulus. The addition of lithium to aluminum can also increase strength, provide precipitation hardening and decrease density.

14. Zirconium is added to aluminum to form a fine precipitate of intermetallic particles.
a) True
b) False
Answer: a
Clarification: The given statement is true. Zirconium is added to aluminum to form a fine precipitate of intermetallic particles that inhibit recrystallization.

15. Addition of ______ to aluminum improves fluidity.
a) vanadium
b) silicon
c) manganese
d) copper
Answer: b
Clarification: Addition of silicon to aluminum improves fluidity. It does so by reducing the melting temperature of the alloy. Silicon alone has non-heat treatable effects. But, its combination with aluminum and magnesium makes a heat-treatable precipitation hardening alloy.

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