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Class 11  »  Chemistry  »  p-Block Elements Groups 13 and 14

Aluminium Properties Reactions Uses - UNSOLVED PRACTICE SET

Class 11

Chapter: p-Block Elements Groups 13 and 14 | Topic: Aluminium Properties Reactions Uses

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Class 11

ALUMINIUM PROPERTIES REACTIONS USES - UNSOLVED PRACTICE SET

Topic: Aluminium Properties Reactions Uses

Time: 40 mins | Marks: 30 | Difficulty: Medium

Multiple Choice Questions

Q1. Aluminium is extracted from its ore (bauxite) by:

  1. Electrolysis of molten AlCl₃
  2. Reduction with carbon
  3. Electrolysis of alumina dissolved in molten cryolite
  4. Thermal decomposition

Q2. Aluminium vessels should not be washed with caustic soda (NaOH) because:

  1. Aluminium is less reactive than sodium
  2. Aluminium reacts with NaOH to form soluble sodium aluminate and hydrogen gas
  3. Caustic soda corrodes the vessel slowly
  4. No reaction occurs

Q3. Aluminium oxide (Al₂O₃) is:

  1. Acidic
  2. Basic
  3. Amphoteric
  4. Neutral

Q4. The thermite reaction involves aluminium and:

  1. Iron oxide
  2. Copper oxide
  3. Zinc oxide
  4. Aluminium oxide

Q5. Aluminium forms a protective layer of Al₂O₃ on its surface. This makes aluminium:

  1. More reactive
  2. Resistant to corrosion
  3. Heavier
  4. Brittle

Q6. In the electrolytic refining of aluminium, the electrolyte used is:

  1. Aqueous AlCl₃
  2. Molten Al₂O₃ in cryolite
  3. Aqueous NaOH
  4. Molten NaCl

Short Answer Questions

Q7. Write balanced chemical equations for the reaction of aluminium with:

(a) Dilute hydrochloric acid

(b) Sodium hydroxide solution

Q8. Why is cryolite (Na₃AlF₆) added to alumina (Al₂O₃) during the electrolytic extraction of aluminium? What role does it play?

Q9. Explain why aluminium is used for making cooking utensils despite being a reactive metal. What property makes it safe for this purpose?

Q10. What is the thermite reaction? Write the balanced equation and mention one important application where this reaction is used.

Q11. Your school uses aluminium foil to wrap mid-day meals for students. Explain why aluminium foil is preferred over plastic wrap for hot food, considering both physical and chemical properties.

Q12. Why is anodising done on aluminium articles? What is the chemical process involved, and how does it benefit the article?

Long Answer Questions

Q13. Describe the extraction of aluminium from bauxite ore by the Hall-Heroult process. Include:

(a) Purification of bauxite (Bayer's process)

(b) Electrolysis of alumina in molten cryolite — reactions at anode and cathode

(c) Why is the anode made of carbon and why does it need periodic replacement?

(d) Environmental concerns associated with aluminium production

Q14. Discuss the amphoteric nature of aluminium and its compounds. Illustrate with chemical equations showing:

(a) Reaction of aluminium metal with acids

(b) Reaction of aluminium metal with bases

(c) Reaction of aluminium oxide with acids and bases

(d) Reaction of aluminium hydroxide with acids and bases

What does "amphoteric" mean in this context?

Q15. Aluminium has transformed Indian industry and daily life in remarkable ways. Discuss:

(a) Why aluminium is preferred over steel in the Indian Railways for manufacturing coaches (LHB coaches)

(b) The use of aluminium in India's space program (ISRO) for satellite structures

(c) Why aluminium recycling is a booming industry in India and its environmental benefits

(d) The health concern related to aluminium cookware and why anodised aluminium is considered safer

Numerical / Application-Based Problems

Q16. In the Hall-Heroult process, a current of 100,000 A is passed through the electrolytic cell for 8 hours daily.

(a) Calculate the total charge passed through the cell in one day.

(b) Calculate the mass of aluminium produced per day. (Assume 100% current efficiency)

(c) If the cost of electricity is ₹ 6 per kWh, calculate the daily electricity cost for running this cell at 4.5 V.

[Given: Atomic mass of Al = 27, 1 F = 96500 C, 1 kWh = 3.6 × 10⁶ J]

Q17. An aluminium alloy used in aircraft contains 95% aluminium by mass. An aircraft wing requires 500 kg of this alloy.

(a) Calculate the mass of pure aluminium required.

(b) If aluminium is extracted from bauxite containing 50% Al₂O₃, calculate the mass of bauxite needed.

(c) If the extraction process has 90% efficiency, calculate the actual mass of bauxite required.

[Given: Atomic masses: Al = 27, O = 16]

Q18. A thermite mixture contains 54 g of aluminium powder and 160 g of iron(III) oxide (Fe₂O₃).

(a) Write the balanced equation for the thermite reaction.

(b) Identify the limiting reagent and calculate the mass of iron produced.

(c) Calculate the mass of the excess reagent left unreacted.

[Given: Atomic masses: Al = 27, Fe = 56, O = 16]


Total: 30 Marks | Time: 40 mins

Explore more topics in p-Block Elements Groups 13 and 14

Group 13 Boron Family General Trends Boron Allotropes and Compounds Borax Boric Acid Diborane Group 14 Carbon Family General Trends Allotropes of Carbon Oxides of Carbon CO and CO2 Silicon Silicates Silicones Zeolites Anomalous Behaviour of Carbon