Practice Questions for Science Class 10th "Metals and Non-metals"

Multiple Choice Questions (MCQs):

1. C) Oxygen - Oxygen is a non-metal.
2. A) Aluminium - Aluminium is the most abundant metal in the Earth's crust.
3. A) Good conductors of heat and electricity - This is a characteristic property of metals.
4. B) Mercury - Mercury is liquid at room temperature.
5. B) Negative ions - Non-metals tend to gain electrons, forming negative ions.
6. C) Metallurgy - Metallurgy is the process of extracting metals from their ores.
7. C) Copper - Copper is used in electrical wiring due to its high electrical conductivity.
8. B) Oxidation - The reaction of a metal with oxygen is an oxidation reaction.
9. D) Soft and malleable - Ionic compounds are typically hard and brittle, not soft and malleable.
10. B) Oxygen - Oxygen is essential for life and is a major component of air.
11. B) Malleability - Malleability is the ability to be hammered into thin sheets.
12. B) A hydroxide - Metals react with water to form metal hydroxides and hydrogen gas.
13. C) Brass - Brass is an alloy of copper and zinc.
14. B) Magnesium - Magnesium reacts with steam but not with cold water.
15. A) Silicon - Silicon is extensively used in making semiconductor chips.
16. B) Their ability to react with other elements - The reactivity series is based on how readily metals react with other elements.
17. A) They have free electrons - Metals conduct electricity due to the mobility of their valence electrons.
18. D) Bronze - Bronze is not a form of iron; it's an alloy of copper and tin.
19. B) Galvanization - Galvanization involves coating iron with zinc.
20. C) Hydrogen - When metals react with dilute acids, hydrogen gas is produced.

Short Answer Questions:

21. Ore Definition: An ore is a type of rock that contains enough minerals with important elements like metals, making it economically viable for mining and extraction.
22. Metallurgy: It's the science and technology of extracting metals from their ores and refining them.
23. Malleability and Ductility: Metals have a structure where layers of atoms can slide over each other, allowing metals to be shaped without breaking, due to metallic bonding.
24. Amphoteric Oxides: Oxides that can act both as acids and bases, like aluminium oxide (Al₂O₃), which reacts with both acids and bases.
25. Reactivity and Extraction: More reactive metals require more energy-intensive methods like electrolysis, while less reactive ones can be smelted or reduced with carbon.
26. Sodium with Water: Sodium reacts vigorously with water to form sodium hydroxide and hydrogen gas: 2Na + 2H₂O → 2NaOH + H₂.
27. Acidic Oxides from Non-Metals: Non-metals generally form acidic oxides because they share electrons with oxygen, creating compounds that dissolve in water to form acids.
28. Alloy vs. Pure Metal: An alloy is a mixture of metals or a metal with another element, improving properties like strength or resistance to corrosion, unlike pure metals.
29. Preventing Rusting: Methods include painting, galvanizing, alloying, and using inhibitors or keeping iron in dry conditions.
30. Carbon in Iron Extraction: Carbon reduces iron oxide in the blast furnace, forming carbon monoxide which further reduces the oxide to iron.
31. Oxide Nature and Reactivity: More reactive metals form basic oxides, less reactive ones might form amphoteric or neutral oxides, and the least reactive might form oxides that are less basic or even slightly acidic.
32. Aluminium in Aircraft: Aluminium is light, strong when alloyed, corrosion-resistant, and has a good strength-to-weight ratio.
33. Copper in Moist Air: Copper forms a greenish layer of copper carbonate (patina) due to reaction with oxygen and carbon dioxide.
34. Corrosion: The degradation of metals due to chemical reactions with their environment, e.g., rusting of iron.
35. Environmental Impacts: Deforestation, soil erosion, water pollution, air pollution, and habitat destruction are some impacts of metal extraction.
36. Ionic Compounds Properties: High melting and boiling points, conduct electricity when molten or in solution, mostly soluble in water, form crystalline solids.
37. Hydrogen not a Metal: Despite having some metallic properties under extreme conditions, hydrogen's electron configuration (1s¹) doesn't match the typical metal's, and it doesn't form metallic bonds at normal conditions.
38. Displacement Reactions: A more reactive metal can displace a less reactive one from its salt solution. Example: Zn + CuSO₄ → ZnSO₄ + Cu.
39. Graphite Uniqueness: Graphite, unlike other non-metals, conducts electricity due to its structure where electrons can move freely within the layers.
40. Distinguishing Metals and Non-Metals:

• Metals: Lustrous, conduct heat and electricity, malleable, ductile.
• Non-Metals: Dull, poor conductors, brittle (if solid).

Long Answer Questions:

41. Physical Properties:

• Metals: Shiny, good conductors, malleable, ductile, high melting/boiling points, form positive ions.
• Non-Metals: Dull, poor conductors (except graphite), brittle, low melting/boiling points, form negative ions or covalent bonds.

42. Reactivity Series and Displacement:

• The series orders metals by their reactivity. More reactive metals displace less reactive ones from solutions. Example: Potassium displacing silver from silver nitrate.

43. Extraction Methods:

• Roasting and Reduction: For metals below carbon in reactivity series (e.g., zinc).
• Electrolysis: For highly reactive metals (e.g., aluminium).
• Hydrometallurgy: Using aqueous solutions (e.g., copper).

44. Chemical Properties Difference:

• Metals: Lose electrons to form positive ions, react with acids, bases, water, and oxygen.
• Non-Metals: Gain electrons or share them, form acidic oxides, less reactive with acids.

45. Reactivity Series and Corrosion:

• Helps predict corrosion rates; more reactive metals corrode faster unless protected. Protection involves using less reactive metals or coatings.

46. Alloys vs. Pure Metals:

• Advantages: Improved strength, corrosion resistance, conductivity.
• Disadvantages: Can be more complex to recycle, sometimes more expensive.

47. Reactivity and Practical Use:

• More reactive metals like sodium are used in controlled environments; less reactive ones like gold for jewelry due to durability.

48. Electrolytic Refining:

• Example: Purifying copper where impure copper is anode, pure copper cathode, and copper ions move in solution to deposit on the cathode.

49. Environmental Concerns:

• Pollution from mining waste, energy consumption, land degradation, and the need for sustainable practices.

50. Metals in Biological Systems:

• Iron in hemoglobin for oxygen transport, calcium for bone structure, magnesium in chlorophyll, and trace metals for enzyme function.

51. Ionic Bond Formation:

• Metals lose electrons to non-metals, forming ionic bonds due to electrostatic attraction. Example: Sodium chloride (NaCl) formation.

52. Oxidation-Reduction in Metals:

• Metals tend to get oxidized (lose electrons) in reactions, while non-metals or other compounds are reduced (gain electrons).

53. Economic Implications:

• Mining creates jobs but can lead to environmental cleanup costs. Recycling reduces the need for mining, impacting economics positively by conserving resources.

54. Electronic Configuration:

• Metals have fewer electrons in their outer shell, donating them easily, while non-metals have more, tending to accept or share electrons.

55. Non-Metals in Industry:

• Silicon in electronics, sulfur in fertilizers and chemicals, chlorine in water treatment, and carbon in various forms for multiple uses.

56. Sustainable Development:

• Efficient use of metals, recycling, reducing waste, and developing alternatives or substitutes for scarce or environmentally damaging metals.

57. Anodizing Process:

• An electrochemical process forming a thick oxide layer on metals like aluminium, enhancing corrosion resistance and aesthetic appeal.

58. Health Effects of Heavy Metals:

• Lead can cause developmental issues, cognitive impairments; mercury affects the nervous system, leading to neurological disorders.

59. Historical Evolution:

• From the Bronze Age to Iron Age, metals have shaped civilization, with each era marked by advancements in metal use.

60. Metallurgy and Technological Progress:

• Advances in alloying, refining, and new metal uses have led to innovations in transport, electronics, construction, and healthcare.

Application-Based Questions:

61. Demonstrating Reactivity Series: Place a piece of zinc in a copper sulfate solution; zinc will displace copper, showing its higher reactivity.
62. Forming Metal Oxide: Heat a piece of magnesium ribbon in air; it will form magnesium oxide (MgO), which is white.
63. Testing Metal or Non-Metal:

• Conductivity: Use a simple circuit; metals will complete it.
• Malleability: Try to hammer the substance; metals will flatten.

64. Magnesium and HCl Reaction: Mg + 2HCl → MgCl₂ + H₂
65. Extracting Copper from Copper Oxide: Heat copper oxide with carbon (coke) in a furnace: 2CuO + C → 2Cu + CO₂.
66. Preventing Iron Rusting: Apply paint, galvanize, or use rust inhibitors; keep in a dry, oxygen-free environment.
67. Conductivity Experiment: Wire up a circuit with both a metal (like copper) and a non-metal (like sulfur) to see which conducts electricity.
68. Zinc and Silver Nitrate Prediction: Zinc, being more reactive, will displace silver from silver nitrate: Zn + AgNO₃ → Zn(NO₃)₂ + Ag.
69. Copper Purification via Electrolysis: Use impure copper as anode, pure copper as cathode, and copper sulfate solution. Copper ions move from anode to cathode
70. Hydrogen Production from Magnesium:

• The reaction is: Mg + 2HCl → MgCl₂ + H₂
• Molar mass of Mg = 24 g/mol
• 10 grams of Mg is 10/24 = 0.4167 moles
• Each mole of Mg produces 1 mole of H₂
• Mass of H₂ = 0.4167 moles × 2 g/mol = 0.833 grams

Critical Thinking Questions:

71. Materials Choice in Construction and Manufacturing:

• The choice reflects the need for materials that offer durability, conductivity, corrosion resistance, and cost-effectiveness. For instance, steel structures in buildings for strength, copper in electrical systems, and aluminum in aircraft for lightweight yet strong properties.

72. Non-Renewable Metal Resources and Sustainability:

• The finite nature of metal resources poses sustainability issues; it encourages recycling, finding substitutes, and improving extraction efficiency to reduce environmental impact. Long-term, this could lead to resource scarcity unless managed with sustainable practices.

73. Noble Metals:

• Metals like gold, platinum, and silver are called "noble" due to their resistance to corrosion and oxidation. Applications include jewelry, electronics (gold in connectors for conductivity), and catalysts (platinum in catalytic converters).

74. Corrosion and Infrastructure:

• Corrosion can lead to structural failures, requiring maintenance or replacement. Mitigation includes protective coatings, alloying, cathodic protection, or using corrosion-resistant materials. This impacts cost, safety, and longevity of infrastructure.

75. Metals in Green Energy:

• Metals play a pivotal role in renewable energy technologies:
  • Solar Panels: Silicon, silver for conductivity.
  • Wind Turbines: Steel, rare earth metals in magnets.
  • Batteries: Lithium, cobalt, nickel for energy storage.
• Efficient use and recycling of these metals are crucial for sustainability.

76. Recycling and Global Economy:

• Recycling could shift economies towards circular models, reducing raw material demand, lowering extraction costs, and creating jobs in recycling industries. It might also stabilize metal prices and reduce geopolitical tensions over resources.

77. Ethical Mining Practices:

• Ethical considerations include:
  • Community Impact: Mining can disrupt local communities; ethical practices involve fair compensation, community development, and respecting indigenous rights.
  • Environmental Impact: Implementing sustainable mining practices, land reclamation, and minimizing pollution.
  • Worker Rights: Ensuring safe working conditions, fair wages, and against child labor.

78. Alloys and Technological Advancements:

• Alloys have allowed for:
  • Strength and Durability: Steel alloys for buildings, ships, and cars.
  • Conductivity: Copper alloys in electronics for better performance.
  • Special Properties: Titanium alloys for aerospace due to strength-to-weight ratio.
• These advancements have driven technology forward by providing materials tailored to specific needs.

79. Economic vs. Environmental Balance in Mining:

• The balance involves:
  • Economic Benefits: Job creation, economic development, revenue from exports.
  • Environmental Costs: Habitat destruction, pollution, carbon emissions.
  • Optimization: Through regulations, technological innovation for cleaner mining, rehabilitation of mined areas, and promoting recycling.

80. Metals in a Post-Carbon Economy:

• In a future with minimized carbon use:
  • Renewable Energy: Increased demand for metals in solar, wind, and electric vehicle technology.
  • Efficiency: Focus on using metals that are abundant or easily recyclable.
  • Extraction: More sustainable methods, perhaps with lower energy inputs, or extracting metals from waste or seawater.
  • Substitution: Research into alternative materials or reducing metal usage through design or new technologies.